Proper light wattage to maintain a 55g reef

[AndrewT]

i have 4 t5s and my corals just seem to be taking forever to grow. Im thinking that my lack of light may be somewhat to blame. Im trying to add two more t12 bulbs very soon. Id love to upgrade to mh but i cant afford to upgrade just yet with tuition and christmas coming. Will this be sufficiant to accelerate growth and provide sufficiant lighting in my tank for all my sps and clams.

[GKarshens]

Hard to say. It may not be the light. It could be lack of calcium, less than ideal water conditions, or something else. SPS do like a lot of light so more may help but I think I would stay with the T5s since you already have them and add 2 more T5s instead of T12s.

[Robb in Austin]

I agree with Gabriel.

We need to know more about the tank and water conditions.

What kind of T5's are you running? Canopy? Look into retros if you have a canopy, they can be done cheaply.

[AndrewT]

I agree with Gabriel.

We need to know more about the tank and water conditions.

What kind of T5's are you running? Canopy? Look into retros if you have a canopy, they can be done cheaply.

Thanks guys... as far as water conditions everything is great. Nitrates and phosphates 0, ph a little low about 7.8, kh 10.5-11.5 calcium is actually a little high at 520. I did want to get t5s and put them in there but im getting a great deal on the t12s from colin on here so i decided to go with those. i believe they are super actinic bulbs from what hed said. They are retro fit i believe so they will be mounted in the canopy.

[GKarshens]

Those are really weird numbers. Your Ph is really low for having your alk that high. You might have CO2 pooling on your surface. Do you have fans on the surface or much surface agitation from power heads?

I still say keep your lights all the same. You will be happier in the long run.

[AndrewT]

Im not sure ive had some problems with my kh and ph. with the kh being about 10 and my ph allways being lower. Ive tried to adjust it with b ionic but not really any luck. My fan that i have is built into my light fixture. My power head that i have is sitting about mid tank. Im not really to familiar with co2 pooling. As far as the lights I figured that more light would help. any reasoning behind sticking to the same lights vs the combo of the two. I just figured its a good deal and more light certainly wouldnt hurt. Well any info is certainly helpful thank you gabe

[GKarshens]

CO2 can build at the surface of the water if you have a canopy or a braced tank. It is heavier than air so it sits there and blocks the gas exchange our tanks need. That is why a fan blowing across the surface or powerhead pointed toward the surface will break that up. It should help with PH. Also cracking a window in the house can help along with that.

I just think that for ease of bulb replacement and getting the color where you want it, it would be easier with all the same. If those will work for you go for it. I have not really heard of anyone using T12s to grow coral before though. They may not have the penetration strength of the T5s.

[Dena]

Just popped into this thread...very interesting to know. Now I've got a question...my kH was well over 13 when I did my last test, but my PH was was about 8.2. I didn't see anything about lowering the kH, just increasing it. Should I be concerned?

Dee

CO2 can build at the surface of the water if you have a canopy or a braced tank. It is heavier than air so it sits there and blocks the gas exchange our tanks need. That is why a fan blowing across the surface or powerhead pointed toward the surface will break that up. It should help with PH. Also cracking a window in the house can help along with that.

I just think that for ease of bulb replacement and getting the color where you want it, it would be easier with all the same. If those will work for you go for it. I have not really heard of anyone using T12s to grow coral before though. They may not have the penetration strength of the T5s.

[GKarshens]

13 is pretty high. I would look at doing a water change with a salt that has a low KH like Tropic Marin Pro.

[AndrewT]

I'm guessing the film sitting on the top of the water may be the co2 sitting on the surface of the water? I do have a canopy on my tank I try and leave it open most of the day I've also got on hob skimmer and refugium then a small power head and my ehiem pro going do I still need more circulation in there? Also with the ca being around 520 can that be harmful? It's allways pretty high and never seems to drop. Thanks again

[caferacermike]

My simple observations would be that adding more actinic lighting won't really help with coral, only color. Adding 8k-12k will really help them grow. 6.5k can cause them to grow at a much faster speed, it is the same spectrum as the sun, however the corals will all brown out in color and algae may become rampant. A "safe" bulb is 12-14k. Good growth with good color.

The film you speak of is not the CO2, but instead a potential time bomb. Indeed the film is preventing water to air gas exchange and would indeed cause CO2 to build up in the tank. CO2 is invisible, you be able to see it. The sheen is from waste oils being produced in the tank. How well is the skimmer working? It should be removing this oil. Consider running a true sump under the tank instead of just the HOB fuge. The overflow box will really suck that film off the top of the water, plus the falling water will mix with oxygen thus displacing the CO2. I'd be willing to say that your tank is a candidate for having to much CO2 in the water and that it is causing the PH to drop down. This happens to a lot of reef tanks that don't run a refugium, or those that do but keep the lighting on the same timer as the tanks lights. What happens is that while the lights are on all day, the water becomes oxygenated due to your algae using CO2 for respiration and photosynthesis, they then exhale O2. At night when all lights are down your photosynthesis is at a minimum, plus with the breakdown of organic wastes, CO2 levels rise causing the PH swing. Add to that the film of oil on the water preventing the transfer or "gassing off of" CO2 to atmosphere.

Edited November 27, 2008 by caferacermike

[AndrewT]

thanks to all who replied. Very very useful information. I've got some very good ideas to get the tank up to par. I'll admit that I'm still new to the hobby and learning as I go,but arc has been very helpful and has helped answer many questions I've had. My tank was very poorly taken care of when I bought it,but it's slowly but surely coming along. Thanks again