[TimH07]

I'm a bit at a loss, some of the sps i got a while ago are doing great while others are not doing so well.

For instance

the coral on the right here has turned an amazing crimson color and is growing like a weed, while the one to the left has "flaked" alot of the lower region away and is just calc skeleton, though the top is still colored and i think i can still see polyps.




this fella has turned a very light pinkish white color and the polyps are not green anymore, more a tan (loss of zooanxthela? i spelled that wrong)




now i know there is a large variety of things that can cause this, im trying to narrow it down.

SG is 1.024 @ 79 degrees

Temp ^

po4 --0
ammonia 0
nitrate 0
nitrite 0
calc---420 normaly closer to 450

DKH 11 (this drops quite fast in my tank i use B-ionic 2 part and for a peroid had to add every day it ups it by 2.07 dkh as instructed) but ive got it holding around 9-10 for the most part.

im raising the temp to around 80-81 but i had problems with my cheto at higher temps and its happy around 79-80


as for lighting i have the nova extreme pro 4x24 Watt T-5's with 1 10k daytime, 1 powerchrome pure actinic, and 2 actinic plus. for a more blue spectrum.

The corals in question are at the mid tank level as well. i even have sps lower in the tank doing better and appear to be almost the same species.

a proper ID on those would help me out as well, Dr. Mac just kinda told me they were either acropora or montipora when i got them.

i have 3 that are failing, and 7 that are thriving, most are at the same level or not too far off, thats whats frusterating to me.

[Ninong]

Your lighting is inadequate for most SPS, especially Acropora spp. You have only one 24w T5 lamp that is putting out anything approaching decent PAR, the 10,000K lamp. Your other three lamps are all actinic. That's nice except that actinics are less than half as powerful as regular "daylight" lamps. I'm including your 10,000K lamp in the "daylight" category even though most people consider only 6,000-6,500K lamps as true "daylight" lamps.

It doesn't matter what your water volume is or what your "watts per gallon" may or may not be. The only thing that matters is the intensity of light that strikes the surface of the corals. Your lighting is not intense enough for SPS corals.

You should consider raising your SG to at least 1.025. It's a little on the low side right now.

It's fine to use the B-Ionic two-part product to maintain calcium and alkalinity, if that's the way you want to go; however, it should be dosed daily! I have no idea where you're reading about upping your alk by 2.07 dKH with a single dose and that being considered a good idea. That's a terrible idea! You should never aim to raise your alkalinity by that much with a single dose of anything. Sudden changes in either alkalinity or pH can be harmful to corals. These parameters should be changed gradually, not suddenly. In fact, just about everything should be changed gradually.

It you want to use a two-part product, such as B-Ionic, then you should dose it daily. Adjust the dosage as necessary. You don't always have to add equal amounts of each component. Sometimes it may be necessary to add more of one than the other, depending on your measurements.

All three corals pictured are Acropora. I can't see the two in the first picture clearly enough to even begin to guess at the species. I could guess at the bottom one but that's not important. Most Acropora corals can adapt to a wide range of light in their natural habitat but your lighting is really weaker than what most of them can work with. There are other factors at play that may or may not be applicable in your case. For example, almost all Acropora corals require strong water current for good health. I notice, for example, in your bottom photo that the coral is sliming. With strong water current, that wouldn't even be noticeable. BTW, the polyps on that coral still look light green to me.

I agree with raising the temperature from the current 79 degrees to 80-81 degrees but temperature is not part of your problem right now.

As for the coral on the left in the first picture, the one you say is sluffing off tissue from the bottom but still has some coloration and visible polyps at the top, you might want to consider removing it and fragging off the top. If the bottom part is visibly dead, you might want to take it out of the tank, cut off the top part that still has some coloration and some polyps and put that part back into your tank. You can attach it will a little bit of epoxy if you like. That's probably the way I would go but this is a judgment call that has to be made by looking at the coral in question.

[TimH07]

i forgot to mention they are T5HO bulbs, which produce between 95-105 lumens per watt and supposedly more than 50% more intensity than typical T5's. and the corals are 12 inches from the top. i took one of the 10kk bulbs out a while ago for the pure actinic, that could be where i messed up.

i want to reply to more of this but i have to run atm, i'll be on later to discuss it more, im kinda confused yet

[Ninong]

Originally Posted by TimH07

i forgot to mention they are T5HO bulbs, which produce between 95-105 lumens per watt and supposedly more than 50% more intensity than typical T5's.

"Typical T5's" are not used in the hobby. It's only the HO T5's that are used. I know exactly what your lighting is and I think it's inadequate for most SPS, especially Acropora. You may be able to maintain some species of SPS (including even Acropora) if you place them high in the tank and directly under the center of the lamps. That would be the place with the highest light intensity. You might need to switch to a combination of three 10,000K lamps with only one actinic lamp in order to maximize intensity.

... and the corals are 12 inches from the top. i took one of the 10kk bulbs out a while ago for the pure actinic, that could be where i messed up.

Your one 10,000K lamp is probably producing about the same total amount of light intensity as all three of your actinics. It's definitely more than two of the actinics and probably closer to equalling three of them.

I dug up a few of my old posts on light that you might find interesting. Some of these go back to 2001: Here, here, here, here, here, here, here.

[TimH07]

Never a disappointing reply

that was alot of reading but i understand things alittle better now.

to reply to earlier post:

my SG is lower than what should be because i go out of town for 3 days at a time often and with no auto top off, i come home to 2 inches evaporation and a SG of 1.028 which worry's me so i kinda compensate by keeping it just a tad lower so if im gone too long it goes TO normal SW. im not sure which is beter practice, but since alot of ppl say they keep theirs at 1.023-1.026 i'd like to think things would be somewhat ok. i know 35 ppt is ideal.

on the fixture subject, the light cost me 176 dollars, the corals cost me 5 dollars each i cant afford the halides at this time, but i understand why i need something like that now. about the bulbs, would changing to 6500k bulbs help? i know that would be really on the white side as far as looks, but im more for keeping things alive.

the B-ionic subject i was mispoken, the instructions say to add no more than 1 ml per gallon capacity per day to raise it 2.07 dkh along with the calc dosage of equal parts.

i guess what struck me the weirdest was how i have acros thriving and growing like weeds and the one just beside it dying.

last but not least, the pictures i used were when i got the corals, not how they look now, the second pic is what it did look like when i got it.

again thank you for your in depth knowledge, i am going to take a break now, my eyes are going to bleed from all the reading.

~Tim

Edit, forgive my lack of grammer/punctuation i type faster than i think and dont care about looking pro on the internet

one last thought, photo period, ive heard some say longer can compensate for less lighting, which at face value seems logical, but im not gonna experiment by nuking my tank with 16 hours of light, i keep mine on 12.5 hours (the extra half is so i can enjoy my evenings looking at them a tad longer.

[Ninong]

Originally Posted by TimH07

my SG is lower than what should be because i go out of town for 3 days at a time often and with no auto top off, i come home to 2 inches evaporation and a SG of 1.028 which worry's me so i kinda compensate by keeping it just a tad lower so if im gone too long it goes TO normal SW. im not sure which is beter practice, but since alot of ppl say they keep theirs at 1.023-1.026 i'd like to think things would be somewhat ok. i know 35 ppt is ideal.

That's a problem. It's better to avoid such wide swings in salinity in a reef aquarium.

on the fixture subject, the light cost me 176 dollars, the corals cost me 5 dollars each i cant afford the halides at this time, but i understand why i need something like that now. about the bulbs, would changing to 6500k bulbs help? i know that would be really on the white side as far as looks, but im more for keeping things alive.

As I said previously, I would probably try three 10,000K lamps and one actinic. The 6500K won't look white, it will look slightly yellow.

one last thought, photo period, ive heard some say longer can compensate for less lighting, which at face value seems logical, but im not gonna experiment by nuking my tank with 16 hours of light, i keep mine on 12.5 hours (the extra half is so i can enjoy my evenings looking at them a tad longer.

You shouldn't even think of keeping the lights on 16 hours a day. The very longest would be 14 hours/day but I think 13 hrs/day is a better maximum photoperiod. For proper respiration, you need at least 10 hrs/day without light.

Yes, it's true that an extended photoperiod can compensate to a certain extent for lower light but this is a really complicated subject to try to explain in less than 5,000 words. Let's put it this way: 13 hrs/day is better than 8 hrs/day if the 8 hrs/day is inadequate to begin with due to lower light intensity. The total irradiance during the time the light is on is cummulative. However, having said that, you still need a minimum amount of intensity to begin with for the various different corals or you will have problems that even a 14-hr photoperiod won't solve.

The various different types of corals have certain minimum light requirements. This is strictly a matter of the intensity of the light that strikes the surface of the coral (assuming appropriate spectral distribution) and it has nothing to do with the source of the light (whether metal halide, T5 HO, VHO, Compact Fluorescent, LED, whatever), and it has absolutely nothing to do with the volume of water in the tank. Indirectly it has to do with the height of the tank because that affects the distance of the coral from the bottom of the light fixture. And once you get much above about 27" tall, metal halides are about the only thing that will work at the present time. LEDs and T5 HO fixtures are really inadequate for tanks that are 30" tall. They are certain fine for tanks that are only 24" tall, provided you have enough of them. LEDs are supposed to be the way of the future but I don't believe they're there yet. You could probably get by with T5 HO lamps over a 30" tall tank but only if you covered the entire surface of the tank with lamps in individual reflectors. I still think metal halides are better for 30" tall tanks.

[NanoReefer1]

Now since you recommend a maximum photoperiod of 13 hours I am left wondering if that includes moon lamps?
Was thinking about getting one, and not sure of the benefits of it...
Also second a pondering led me to wonder if acitinic are not as useful then what is the purpose of them still being around? and If the benefits of acitinic are less or non-existent would you suggest that I replace it with another 10,000K bulb?


Thanks for your time.

[Ninong]

Originally Posted by NanoReefer1

Now since you recommend a maximum photoperiod of 13 hours I am left wondering if that includes moon lamps?
Was thinking about getting one, and not sure of the benefits of it...

No, the maximum daylight photoperiod has nothing to do with true moonlights.

(You may wish to review Steve Tyree's comments on light in this article.)

The natural light of the moon does not interfere with respiration. Remember that photosynthesis requires light and respiration takes place in the absence of light. Those are the two phases of the photosynthesis process. At the equator, the natural cycle of daytime and nightime is about 12 hours of each all year.

So a natural photoperiod for a reef aquarium would be 12 hrs of light and 12 hrs of darkness. However, it's perfectly fine to cheat a little and go with a photoperiod that is either slightly longer or shorter than that. Probably the most common photoperiod adopted by reef hobbyists who use both metal halides and fluorescent actinic supplementation is for the metal halides to be on 10 hours per day and the actinics 12 hours per day.

A true moonlight would be controlled so that it came on and went off in synch with moonrise and moonset and its intensity would be controlled to match the intensity of the phases of the moon. There are electronic controllers that are pre-programmed to do this. You might even be able to do this manually but it would require a tremendous amount of dedication. You would need to use a blue incandescent lamp (25w would do), a dimmer and a 24 hr timer. The Navy has a website where you can look up sunrise/sunset and moonrise/moonset times for any location worldwide (just enter longitude and latitude). (P.S. -- Enter the longitude and latitude for the natural reef location you wish to simulate.) Then each day you would reset your timer to come on and go off at the correct moonrise and moonset times. You would also have to reset your dimmer every day to match the current phase of the moon.

We have discussed moonlight previously in this forum a lot. I just ran a search using my name and "moon" and got 86 hits. From one of my previous posts:

In order to simulate natural moonlight you need a computer program that matches moonrise and moonset as well as intensity. Just remember that irradiance from the full moon (which is only once every 29.5 days) is 0.01 micro-Einsteins per square meter per second compared to normal noontime solar irradiance of 2,000 micro-Einsteins per square meter per second. Also, keep in mind that for two-thirds of the month the irradiance from the moon is less than half its full moon intensity.

You cannot see much in the tank even on full-moon nights. The intensity of moonlight is only above 70% of full-moon intensity for the two days before and two days after the full moon -- a five day period. And don't forget that a lot of the time the moonlight will be on during the daytime when the metal halides are on and it won't even be noticed at all. If you want to view the tank at night, you should use a red flashlight. Red light is not "seen" by most marine animals since it is filtered out early in the water column in nature and is not part of their environment.

To emphasize my point on moonlight intensity a bit more: For 9 days of the month the intensity is less than 0.0008 micro-Einsteins per square meter per second -- that would be the period closest to new moon when the intensity is less than 1/12 of full-moon intensity for the four days before and the four days after the new moon.

Unless your moonlight is controlled so that it exactly matches the natural cycle of the moon in intensity and moonrise/moonset it is just a nightlight. And if it is too bright it could confuse the tank's inhabitants. The purpose of a moonlight is to simulate natural conditions in the belief that this will induce corals, clams, etc., to spawn in captivity. That's because one of the natural cues is moonlight. The other natural cue is the temperature of the water. So you would also want to have your tank's water temperature controlled to match natural conditions if you're trying to duplicate the mass spawning on the Great Barrier Reef.

Most of the so-called moonlights that I have seen are too bright. And having them on every night after the daytime lights go out defeats the purpose of trying to simulate natural conditions. In other words, they are nothing more than nightlights for the benefit of the human being wanting to look at the tank at night. That would be their only benefit.

Also second a pondering led me to wonder if acitinic are not as useful then what is the purpose of them still being around? and If the benefits of acitinic are less or non-existent would you suggest that I replace it with another 10,000K bulb?

Actinics are VERY useful. The ONLY reason I suggested that Tim remove two of his three actinics and replace them with 10,000K lamps is because he doesn't have enough light intensity right now and that would be one way to increase the total intensity.

Actinics emit at either 420 nm or 450 nm. Usually the ones that emit at 420 nm are called "true actinics." It would take too long to explain why they are useful but I have covered this in previous threads. Actinics are also nice if you want to see fluorescence in some of your tank's inhabitants. Most people set their actinics to come on one hour before the main lights and go off one hour after the main lights.

It's not that actinics are not useful and desirable, they certainly are, it's just that if your lighting options are limited and you are forced to make a decision to increase the total intensity of your fixture, switching to three 10,000K tubes and one actinic tube will provide more intensity than one 10,000K and three actinics. That's because a 10,000K fluorescent lamp has more than double the intensity of a comparable size actinic fluorescent lamp.

[zhenya]

Originally Posted by TimH07

I'm a bit at a loss, some of the sps i got a while ago are doing great while others are not doing so well.

Tim, how long exactly is "a while ago"?

To add to what Ninong had said already, your "sps" corals are fragments of the colonies. It takes some frags anywhere from four to six month to acclimate, encrust and begin to grow. They begin to color up soon after that.
Your tri-color frag is a bit bleached but it should color up if you stay on top of your water parameters and keep them consistent(salinity, calcium and alkalinity levels).

[dendro982]

If I may add some bits at much lesser level, all IMHE (I'm non-photosynthetic reefer, no sps expert ):

TimH07:
I have some sps (no acropora, just montipora, birdsnest, stylopora, pocillopora, porites, pavona) in 20g tank with 110W PC with no problems, but coloration could be better. Nothing from what you described should cause death and bleaching - I had some instability in this tank too. More of this: one of your corals is growing like a weed, so the conditions are acceptable.

1. Is it possible, that the flow is too strong or almost absent, where the affected corals are located? Or they are close to the place, where the additives are added into the water?

2. Could it be the very high magnesium, 1600ppm+? My pavona started to bleach, then I treated tank with Tech-I from bryopsis. All restored after normalization of the Mg level.

3. In my tank bleaching and death of sps were observed only when some toxic inhabitants died unnoticed. If you have sea cucumbers, serpent stars, cynarina or xenia - take a look at them, mine were noticeable affected.

In this case helped frequent carbon change and increased water changes (after removing the victims, of course). Porites recovered from snow-white color.

About tank parameters: I'm keeping SG at 1.026, with fluctuations sometimes, temperature 78F up to 82F in summer, your dKH 9-10 is good - I'm trying to pull mine at this level all the time.

Light: I tried
- 50% 10,000K and 50% actinic,
- 10,000K only, and, as was said,
- 3:1 10,000:actinic, and like this the best, seems that coloration is better with actinic added.

It's all I could think of.

Moderators:
I know, that it is not my area, but just trying to be helpful. If I named something improperly or assumed the impossible - please forgive and correct. I tried to keep my post withing logic parameters - changes - effect. OK?

[TimH07]

thanks for your reply as well dendro, all help or advice is welcome. i think a big part is flow, the affected corals in fact had less flow than others, no doubt light is a factor, but the ones with high flow are doing nicely. im considering adding a MH fixture as a possible 10-2pm booster, if anyone knows of such a hang on type fixture.. something small just to add to my current light let me know.

~Tim

[Poseidon]

Ninong, I have to respectfully disagree with the statement about the actinics not producing much PAR. The Actinic Plus bulb from ATI/Geismann actually produces a considerable amount of PAR. I run a total of 5 bulbs, and only 2 of them are "white" one is a 6.5K GE Star Coat, and the other an ATI Pro Color which actually has the same PAR as a Actinic Plus. (I can't find the RC link at the moment, but I will...)

When I made my switch to T5 I thought I would have issues with not enough light, and I found the opposite to be true, I bleached several pieces that were near the top UNDER a halide when I changed.

In a 4 bulb fixture using 2 whites and 2 blues may be more then enough, I have seen pictures of tanks with 6 bulbs and only 2 are white, the rest blue... I would never have believed it myself, but T5 can and will grow SPS even on the sandbed, in a 24" deep tank.

[Ninong]

Originally Posted by Poseidon

Ninong, I have to respectfully disagree with the statement about the actinics not producing much PAR. The Actinic Plus bulb from ATI/Geismann actually produces a considerable amount of PAR. I run a total of 5 bulbs, and only 2 of them are "white" one is a 6.5K GE Star Coat, and the other an ATI Pro Color which actually has the same PAR as a Actinic Plus. (I can't find the RC link at the moment, but I will...)

See if you can find any reliable test results. I'm talking about the sort of tests that Sanjay Joshi runs on metal halide lamps. I don't remember seeing anything on T5 HO lamps but I do remember seeing tests on other fluorescent lamps but that was a good six or seven years ago. Those test showed that 10,000K lamps were more than twice as intense as actinic lamps when measured in lumens. Virtually nobody runs tests on fluorescent lamps with a PAR meter. It would be nice if they did. However, if the 10,000K lamp produces more than twice as much intensity as measured in lumens, you can assume that it produces much more PAR, too.

It would be nice to see some reliable test results for T5 HO lamps. I'm talking about measuring the lumens (and PAR) at a fixed distance from the center of the lamp. I believe Sanjay usually uses 18" for his metal halide measurements. I know that T5 HO lamps have been measured with and without individual reflectors and the individual reflectors make a big difference.

So the test would be to measure the intensity of a single T5 HO lamp in an individual reflector at a distance of 18" from the center of the lamp. Then you would repeat the same test with 10,000K, true actinic, actinic blue, etc. In other words, all the various colors that T5's come in and see what the differences are. There is not much doubt in my mind that the 10,000K would produce much more intensity than the true actinic, which should be emitting at 420 nm. I'm talking about more than double.

[Poseidon]

I agree Ninong, but the Actinic plus is not really a true actinic bulb, it is more like a blue bulb. The link I am looking for is by The Grim Reefer, and I am not sure if he did it with a PAR or LUX meter, but it was at least consistent. I think there was at least 10 or 12 bulbs if not more involved. (I'm not a premium member at RC, so.... no searching for me.)

I am hoping to get an answer to a PM over there.....

[Poseidon]

Finally...

Reef Central Online Community - T5 Lamp Pictures

Believe it or not the Plus + is VERY close in PAR to the GE 6.5K lamp, which is CRAZY if you ask me...

[L018]

Originally Posted by Ninong

See if you can find any reliable test results. I'm talking about the sort of tests that Sanjay Joshi runs on metal halide lamps. I don't remember seeing anything on T5 HO lamps but I do remember seeing tests on other fluorescent lamps but that was a good six or seven years ago. Those test showed that 10,000K lamps were more than twice as intense as actinic lamps when measured in lumens. Virtually nobody runs tests on fluorescent lamps with a PAR meter. It would be nice if they did. However, if the 10,000K lamp produces more than twice as much intensity as measured in lumens, you can assume that it produces much more PAR, too.

I believe this would work normally, if the light composition was similar.

The problem in our case is that luminous efficiency is a bell curve peaking at about 530nm and zeroing on the blue side in the low 400nm.

PAR on the other hand is relatively high at the 400-500nm range due to its high absorption% and photosynthesis rate amongst chlorophyll a, chlorophyll b, and carotenoids... around 60% when compared to the red component of 10,000k.

The result is our very focused(with respect to wavelength) actinic is received a very low luminous flux rating but actually is quite efficient when described in PAR standards.

[Ninong]

Originally Posted by Poseidon

Finally...

Reef Central Online Community - T5 Lamp Pictures

Believe it or not the Plus + is VERY close in PAR to the GE 6.5K lamp, which is CRAZY if you ask me...

Originally Posted by L018

I believe this would work normally, if the light composition was similar.

The problem in our case is that luminous efficiency is a bell curve peaking at about 530nm and zeroing on the blue side in the low 400nm.

PAR on the other hand is relatively high at the 400-500nm range due to its high absorption% and photosynthesis rate amongst chlorophyll a, chlorophyll b, and carotenoids... around 60% when compared to the red component of 10,000k.

The result is our very focused(with respect to wavelength) actinic is received a very low luminous flux rating but actually is quite efficient when described in PAR standards.

My original suggestion to the topic starter that he change his current combination from one 10,000K lamp and three actinic lamps to three 10,000K lamps and only one actinic lamp was based on the assumption that, in general, a 10,000K lamp can be expected to put out more lumens/PAR than an actinic lamp of the same size. I remember seeing test results (in lumens only, not PAR) several years ago for fluorescent lamps (it was either T8 or power compacts) that showed that the 10,000K lamp produced more than double the intensity (in lumens) of the actinic lamp. This was information supplied by the manufacturer. This was back in the days when there were only two different types of actinic lamps: 420 nm and 450 nm.

Now that there are so many different choices available in T5HO lamps, it is obvious that some of them are "more equal" than others. This sort of reminds me of the testing Sanjay Joshi did, starting several years back, that showed just how great the different in PAR measurements could be between metal halide lamps of the same wattage between different brands and different Kelvin ratings (which, as we all know, are sometimes a joke). Anyway, I remember that the 175w Ushio 10,000K metal halide lamp produced three times as much PAR as the 175w Venture 5,500K lamp. And there were wide differences in PAR readings between the various different brands of 250w and 400w metal halides, often with the same advertised Kelvin rating.

PaulErik had an interesting post in Grim's thread on RC:

GE, Osram, Philips and Narva manufactured T5 HO lamps are built to the same type of standard. They will not light up at the labeled/stamped end of the bulb for a good reason. This is called the cold spot in the lighting industry.



In a fluorescent lamp the light output is determined by the mercury vapor pressure which is determined by the temperature of the liquid mercury. Liquid mercury is deposited on the inner wall of the bulb at the coolest spot. In a stabilized T5HO lamp equipped with a cold spot the liquid mercury will be at the labeled/stamped end of the tube.

With these lamps the cold spot is usually cooled to maintain stable light output and doesn’t require cooling of the whole tube. This technology keeps the lamp very stable because the liquid mercury is located in one spot.

When testing a T5 HO lamp with a cold spot the lamp generally requires a few on/off (heating and cooling) cycles so all of the liquid mercury goes to the cold spot. The lamp should be seasoned for approximately 100 hours. Generally in the lighting industry the recommendation is to re burn (burn in) the lamp for additional 4 hours minimum if the lamp has been switched off for 12 hours or more. A re burn (burn in) is also needed if the lamp is moved or oriented differently. A T5 HO lamp is considered stable if changes in light output are less than 0.5% over a 5 minute period after the burn in period.

Metal halide and fluorescent lamps can be very sensitive and should be tested carefully or the readings will be useless. This is why the lighting industry has standards and specifications on lamp testing.

Grim states in one of his posts that his tests were not performed on individual lamps and he didn't bother to break in some of the lamps. Therefore, it's possible that some of the readings could be off on the high side if the lamp in question was brand new. He also said that one lamps was five months old. I'm not sure how old the others were but I assume most of them were fairly new.

However, for purposes of comparison, his results are interesting. Let's assume that we can accept them at face value just for the sake of discussion. Notice that he measured an ATI actinic blue lamp at 140 PPFD and Giesemann pure actinic at 167 PPFD. Let's compare that to the 348 PPFD for the GE6500, the 341 PPFD for the ATI aquablue, 342 PPFD for KZ coral light, 318 PPFD for Actinic Plus.

It is obvious that the two pure actinics lamps that tested at 140 and 167 compared to a daylight/sunlight lamp (GE6500) at 348. The GE6500 is 2-1/2 times as strong (as measured in PAR by Grim) than the ATI actinic blue lamp. That's pretty much in line with what I saw several years back in a comparison of daylight fluorescent lamps (in lumens) vs. actinic fluorescent lamps (in lumens). This seems to point to the possibility that the so-called "actinic plus" lamp is not a pure actinic, it's actinic plus other phosphors. My original suggestion was based on my belief that actinic fluorescent lamps in general, are much weaker than daylight (or 10,000K) fluorescent lamps when measured in lumens.

It's virtually impossible to start comparing all the spectral qualities of the various fluorescent lamps to see how the compare to known assessory pigment peaks. Sanjay did a pretty decent job of that with metal halide lamps by simply including a spectral distribution graph along with the PAR results.

As far as TimH07's situation is concerned, I would still suggest that he use at least two 10,000K tubes and maybe two actinic plus tubes, if that's looks better to him. That's assuming that the actinic plus tubes actually are close to the 10,000K in PAR output.

Grim's efforts are well intentioned but his methods leave room for improvement. A much more valuable comparison would have been achieved had each tube been tested individually in an individual reflector at a reasonable distance from the tube. I don't see much sense in taking readings 1" from the tube. That result doesn't help us much as far as what we're interesting in, which is how the lamp/reflector combination performs in delivering light to the corals. Each lamps should have been new but then broken in for 100 hours. And each should have been on for four hours before measurements were taken. I'm basing that on the advice given by PaulErik. I hope we don't have to worry about different ballasts affecting the results like we do with metal halides.




P.S. -- I have nothing against actinic lamps. I love actinic lamps. The only reason for changing the mix in Tim's fixture is because he has only four 24w lamps to work with and he's trying to keep Acropora corals.

[Poseidon]

I agree it is not perfect, but it is a tool of use. As for ballasts, YUP they do affect the output, especially Ice Cap ballasts, which overdrive the bulbs. I use 4 overdriven bulbs, and one on a Workhorse 5 ballast, that is used just for dawn to dusk effect.

Overall I am pleased with T5, and I REALLY like the savings on the power bill.

[TimH07]

Thanks again for another good read. Actually ninong the fixture came with 2 10kk bulbs and 2