To much UV?

[Poseidon]

To much UV?
I keep bouncing back and forth over the size of the UV I want. I have already decided the benefits outway the drawbacks, but I want to be sure my UV exposure is adequate. I plan on running the sterilizer in line with my chiller, so I don't have to add another pump, OR I may run it on my return line, depending on what model I get.

My choices are both by Aqua Ultraviolet, and they are both the same dimensions physically. I can't decide between the 25W and the 57W. My tank as it is now, is a 90 with a 30 gallon sump, but I have ambitions to add a 100 gallon sump in my basement. All other things being equal, and my cost difference is not that great, should I just get the 57 and not worry?

Thanks for the input everyone!

[mungus728]

I am in the exact same position as you as far as adding the 100 gallon basement sump. Unfortuneatly I already own the 25 watt model. I could kick myself now for not buying the 57. One thing to mention I have never had a wiper nut w/seal ever last more that 10 months. If you order the Aqua Ultraviolet order an extra wiper nut w/seal. It sucks getting stuck w/o one.

Brian

[Poseidon]

Thanks Brian, actually I am getting the one without the wiper though. It will be plumbed in where it will be easy to clean it, so no need for a potential leak.

[Steven Pro]

What is the flow rate?

[Poseidon]

If I use the chiller pump, the flow rate will be about 400 GPH, if I use my return pump, it will be about 800-900 GPH.

[Ninong]

According to AquaUltraviolet's UV sizing chart, the maximum flow rate to achieve 90,000 µw/cm² with their 25w lamp is 400 gph. The maximum flow rate to achieve the same dosage with their 57w lamp is 1066 gph. If you exceed the maximum flow rate, you won't have enough dwell time to achieve the recommended dosage of radiation. You need 90,000 µw/cm² to kill things such as Cryptocaryon irritans.

Notice that they give a maximum tank size of 150 gallons for their 25w lamp and 355 gallons for their 57w lamp.

I think the 57w size would be the better choice, especially if you intend to move up to a larger tank in the future.

[Poseidon]

Thanks Ninong! I ordered the 57W yesterday. I think the 57W will work perfectly in line with my return pump, even if I get a larger pump for the return from the basement, I can't move much more then 900GPH through my external overflow. (Even though CPR says 1200 GPH)

Next thing to ask is, why do I see people that only run the UV part of the day? I thought the whole point was to make sure your water is as clear as possible.

[Steven Pro]

I would also bet those rating are for when the lamp is brand new. As you all know, lamps lose intensity as they age. Being that you would be at the max flow rate from day one, very soon the UV will become ineffective as the intensity drops as it ages. Getting the 57 watt unit will give you greater leaway.

[Ninong]

According to AquaUltraviolet's chart, those are actually end of life ratings: All UV Dosages are at end of lamp life (EOL) of 14 months (UV dosages are much higher at start of lamp life).

[Poseidon]

According to AquaUltraviolet's chart, those are actually end of life ratings: All UV Dosages are at end of lamp life (EOL) of 14 months (UV dosages are much higher at start of lamp life).

That is why I chose Aqua Ultraviolet! I sure hope they have ethical advertising!

[Ninong]

Next thing to ask is, why do I see people that only run the UV part of the day? I thought the whole point was to make sure your water is as clear as possible.

Probably for the same reason that some people only run their skimmers part of the day and some people only run carbon maybe one or two days per month. You really aren't buying a UV as a clarifier for a reef aquarium anyway, you're buying it to kill nasties. People run UV's on outdoor ponds to avoid the spring algal bloom that would make their pond water turn green but that's not likely to happen in your tank.

If you read enough Tank-of-the-Month type articles, you will find people with UV's who only run them when they add new lifestock to the tank or if they feel there is some other special reason to run them. Others run them all the time. It's up to you how often you want to run it. Hopefully you are already aware of the pros and the cons of running a UV on a reef tank.

[Poseidon]

Thanks Ninong, Yes I am aware of all the pros and cons, I think I am going to be better off with this than I am without it. (Even though I have been fairly successful up to now.)

I know the primary reason for running one is to kill the nasties, but added water clarity is not a bad thing either. Actually I was quite surprised on my last water change, the water was not as yellow in the bucket as I had expected it to be.

My next upgrade is either going to be Ozone, or a bigger skimmer!

[Steven Pro]

If you turn the UV off but don't empty the lines, the inside is going to become covered with a biofilm and when you turn it back on, it is going to be significantly handicapped.

[Poseidon]

I C!

Thanks Steven, I am planning on a 24/7 application, unless I see a reason not to in my specific tank.

[jollopee]

I have been running my UV now for a couple of months on my 90. It was on a seperate pump doing about 800gph but since I put the 20 gal fuge in, it has been running in line with my return pump wich Im guessing is pushing somewhere around 500gph. The UV itself is rated at 900gph. I have been running it 24/7 and absolutely love the clarity of the water and I havent had an outbreak of any nasties either

Todd

[Poseidon]

All hooked up!

I have the 57W model, and I decided to hook it up in line with my skimmer! I run my POS Kent skimmer with a MAG12, it has a ball valve on the pump because the skimmer can't take the full force of the pump at virtually 0 head, so.... What a better thing to do then run the pump first to the UV, then DIRECTLY into the skimmer! One of the knocks on UV is they expel dead algae spores etc into the water, well mine goes into the skimmer where it can be removed, then hopefully CLEAR water from the skimmer into the sump! YAY!

Now to the log to add the UV to the equipment list!

[jollopee]

I never thought of running in line with the skimmer.......thats a dang good idea. Ive got a chore for this weekend I wonder if that is why I keep getting the diatom outbreak on the sand bed.


Todd

[Poseidon]

I never thought of running in line with the skimmer.......thats a dang good idea. Ive got a chore for this weekend I wonder if that is why I keep getting the diatom outbreak on the sand bed.


Todd

Thanks Todd! I kind of thought it made sense. Actually when I opened my sump and I was trying to think of a place to put the UV, this option was the least work! If I put it inline with my return like I thought of before, I would have had to cut PVC, add 90's, reglue, etc etc... My skimmer was plumbed with 3/4 vinyl, which is the EXACT size inlet/outlet I have on my UV. (I ordered the 2", but this came in instead... Oh well)