[Pomme]

Acro lighting!

I have had my tank set-up for 4 months now, and have had acros in it for 2. But my acros are quite dull brown colours, one of them is getting a slight green tinge, but nothin compared to the stuff i see on your acros. The lighting i have over the tank is an arcadia series 3 single metal halide 250 watt



It is the 14,000 kelvin ones, double ended. The lighting unit has also got two 18 watt actinics in it.

Do you think this is the right kind of lighting for my acros to colour up. Oh and yeah my tank is 75 cm, 28 inches or 2 foot deep, with the acros in the middle of this depth?

How long does it take for them to colour up from when you get them home from the LFS?

All help appreciated,
andrew

[Reefland]

Hi Andrew!

The color of the coral will vary from tank to tank, in my opinion. I have purchased corals before that were pink that have turned yellow and I have purchased brown acro's that have turned blue. The difference it lighting intensity and PAR will have an effect on the color. Some people say that 6500k Iwasaki's are best for coloration, others lean towards 20k bulbs. With my 250w 10k DE AB bulbs, I have a mix of colors in our tank ranging from pink to baby blue.

To answer your question, it is impossible to say how long it will take for a coral to color up, if it will at all. Do you have the right kind of lighting? Your corals will answer that question for you.

Scott Z.

[Pomme]

cool thanx scott, if they were growing and doing fine in say 6 months but were still brown woulditbe best to add some more lighting like another halide or t5's,or would it bebest to buy a green acro now and see what it does?

[Reefland]

What size tank do you have your 250w over? And what kind of bulb is your 14k?

Scott Z.

[SueT]

Hi Andrew, I'm going to say I think your lighting may not be intense enough. SPS and in particular acropora spp. like light and some say you can't have enough light for them. I think if after 2 months you are not seeing any color and in fact are loosing color then the lighting may be the problem. I would only add more light if it was another halide. T5's are not going to affect coloration. That is unless your water quality is not up to par. Calcium and alkalinity are also a key player in acropora coloration. Alk. kept in the 12-14dKh will also help in color.

HTH....

[Pomme]

okay my tank is a 100 gal and my acros seem to be growing very well, also my calcium is 440 and dkh is 10? should i raise this a bit?

[kevinpo]

Hi Andrew,
I think you should get a colorful captive grown frag (or 2) from similar lighting (250W @ 12" deep) and see if it maintains its color in your tank. At 12" from the light source you should be able to keep 90% of Acropora species colorful. In my tanks it can take 3-9 months for corals to color up and sometimes I have to move them up or down several times to get the color I like. I have observed that most SPS corals will lighten when light intensity increases, and darken as the light intensity decreases. This is caused by the numbers of Zooxanthellae (which are brown) in their tissue.

At 16" from 400W Ushio 10,000K bulbs (in 36" PFO reflectors) many of my corals became too light with much less color when I moved the 21" below 250W Ushio 10,000K they became a bit too dark. So it is a placement game trying to satisfy our quest for the best color to the human eye. This is not an indicator of the overall health or growth rate of the coral IME.

Regards,
Kevin

[Pomme]

my corals are under 250 watt but are 18 to 25 inches from the waters surface and the light is 250 watt and 6 inches from the water surface. Would it helpif i upgraded my light to the 400 watt 14000k, which has the same wavelenght as my 250 watt?

andrew

[kevinpo]

I would say yes. One note though: move the new light up to about 12" above the tank for 4-5 days then to 9" for 4-5 days to be sure to give the corals time to adjust to the higher intensity. I would also cut back the photo period to 6 hours for 10 days then increase it to 8-9 hours.

Cheers,
Kevin

[Pomme]

so this is likely to increase the colour of the corals, but wont this increase the zooanthalae (spelling?) which are coloured brown which would make the corals look browner or am i on the wrong road?

[kevinpo]

Hello Andrew,
Corals regulate the numbers of Zooxanthellae they have. When the lighting intensity is too low for their nutritional requirements the coral increases the numbers. They have the ability to expel some of them to decrease their numbers when the lighting increases. They can also turn brown for a while when the conditions change (like changing to new bulbs even of the same K value and wattage). As they adjust they return to their original color.... usually Sometimes they turn lighter or darker for quite a long time. If the change is too drastic they can RTN and lose all their tissue in less than 24 hours. This usually only happens when light intensity is increased too quickly for the coral to adjust, (IME) rather than when going to too low of light condition.

Cheers,
Kevin

[Pomme]

cool ill see if i can pick up a 400 watt, i have just got some more lie rockand made a bit of a platform, sonearer the light,and put some of my frags on it, do you think this will help or might it?

[kevinpo]

Most likely they will change color a bit and the growth rate will increase. Keep us posted as to the results.

Regards,
Kevin

[Pomme]

will do ill let you know in the near future hopefully