Do I have enough lighting or too much????

Hello all. New member here so take it easy on me.

I have an older Sea Clear Executive nano tank approximately 10"Hx8.5"Wx17"L (6.25 gals) with a filter chamber in the rear where I keep my filter media (pads and carbon with some nitrate media in the first pre filter and bio balls and ceramic tubes in the second chamber before going back to thetank via a power head. In addition I have a Toms mini canister filter with nitrate media that pulls from the first chamber and expells into the second chamber before back into the tank. All the water perameters are perfect (I think). Phosphate 0, Nitrate 0-5 but ussually 0, Ph 8.2 - 8.3, calcium is ussually at 450 but sometmes spikes to 600, Kh is 8-9, temp runs 74-76. There is approximately 5 lbs. of live rock in the tank. I'm guessing only about 4 gals of water. I change about a gallon a week over 4 changes.

For this tank I light it with a Current fixture with 2 - 18W PC bulbs. One is a SunPaq Dual Actinic 420/460nm and one SunPaq Dual Daylight 6700°K/10000°K. To me that equates to 6 watts per gallon.

The tank has been running for about a year now and most everything looks good. Rock is covering with coraline. No hair algae. One watchman goby, 2 small hermits, an assortment of hitch hiker snails along with one peppermint shrimp to take care of the glass anenomes. I also have some yellow polyps, green star polyps, a small leather coral frag, 2 groups of zoanthids and 2 groups of purple clove polyps. The pruple cloves are doing the best, the GSPs are not doing well and the yellow polyps have wilted away before. I also have a group of mushrooms that has been withering away and almost non extistant.

So, I think the water is good, conditions are stable. Is it my lighting? I've read a bunch but I thought the experience here might supercede all that reading. Thanks.

 

Firstly, Nano's are a bit different than their larger counterparts in WPG. Even though you have 6WPG, you still only have 36 watts of light. This is not over lighting anything IMO. Some people may argue the other way, but thats my thought. I don't really have an answer about why your polyps are withering away. Try raising the temperature to 78 Degrees and try to keep it as constant as possible, even though thats hard with 4 gallons. You might want to think about upgrading to a 10 gallon tank.

Secondly, Welcome to 3reef. Glad to have you.

 

Welcome to 3reef! I am not familiar with lighting requirements... I threw a 250w MH on my 40g so that i would never have this problem Maybe some of the more light knowledgeable member will chime in.

 

First of all, welcome to 3reef!
Now as for your lighting question, the corals that you have are all pretty light tolerant, meaning they will handle a variety of lighting schemes. They are all symbiotic corals as well meaning they house zooxanthellae which provides them essential nutrients.
Your lighting is strong yes, but other things need to be considered as well, such as how much you feed your tank. Another critical question is how long you leave your lights on! Where your corals are placed in the tank? When you have spikes in your calcium level, are you dosing a calcium additive? You have to be careful with elevated calcium levels as alkalinity, pH and magnesium levels become effected, which can stress livestock!
With lighting, all corals can handle a certain amount until it reaches it supersaturation level. Once this point is obtained problems will arise as a result of the corals zooxanthellae having to work extra hard to process the additional oxygen as a result of photosynthesis. Not to jump to conclusions but maybe you leave your lights on too long?
You can alter the amount of light being received by corals through light duration, other factors such as turbidity, dissolved organics, salt creep on your lights or tank cover as well as how long you have had your lights.

 

if you have about 4 gallons of tank water, then you are running around 9 watts per gallon. thats alot for shrooms. try tucking them under a ledge or in a cave or something shady.

 

Thanks everyone. I got some good ideas and suggestions. I reviewing my supplemnt regimine. Most of my calcium spikes are few and far between since I stabilized the Kh at 8-9. I did knock back my lighting last night from 16 hrs antinic to 14 hours and daylight from 14 to 12. Atinics are on one hour before and after. On the shrooms lighting..........I should have known that. The next group I buy will be in the back bottom of the tank and see how they do with less light. The issue of watts per gallon is complex I suppose. Do I use the 4 gallons of water or the tank volume number???? I've always used the tank volume number.

 

To be honest with you, I would not use the watts per gallon rule, because so many reefers get rapped up in the whole lighting issue that they disregard or don't take into consideration all the other important aspects that can have a very substantial impact on the amount of PAR and PUR that is readilly available to your animals below the water surface.