[SPAM]

Hello all, it's been a long time since I posted. I upgraded and made some changes to my tank.
Added VHO lighting (2 actinic, 2 50/50) and made a new canopy. Also removed twin bio wheel, Nitrate was above 50 (some due to die off from poor lighting I'm sure) The polyps were starting to die. I've been doing heavy water changes to get the nitrate down and it's working because the red algae is decreasing.
1) I have new algae though it looks like long strands of hair with bubbles of oxygen attatched.
2) I have a new white scum looking stuff on the water surface.
3) VHO lighting is heating water up to as high as 86 ( 6-8 degree fluctuation) untill I started opening the hood, but it's still 82.
These problems started after we put the new canopy and lighting on. All other water parameters are normal and the nitrate is now undetectable.
The lights are approx 4 inches from water surface. Is that too close.
Would the hood be restricting proper gas exchange also( not enough head room?)
I hope someone has some answers.

[eses]

You'll need to vent the tank or even install fans to make sure the air between the water and the lights gets exhanged from the tank; a big reason many people don't put glass canopies on their tanks.

If you have to run a closed top, a sump would help in this regard, as you can run a open-topped sump and remove some of the heat that way. Also good surface agitation helps.

4" isn't bad, my lights are only about 2" above but they are PC and run 3 fans. You can raise your lights up, but the higher you put them the less effective they are. I would start with finding a permanent ventilation solution. Also, do you have anything seperating your bulbs from the water? My lights are in pastic box with an acrylic cover, air is forced past the bulbs and out which keeps the lights cooler. I have them sitting on a glass lid on the tank, which helps buffer alot of the heat. If you don't have anything blowing the heat from the bulbs that will cause alot of heat problems, and shorten your bulb life.

Worse can scenario is you have to put a chiller on the system, which many people end up having to do.

New algal bloom is probably from the increased light, if your nitrates are 0 you may have excess phosphate or silicate in the water. Keep cleaning it off and changing your water until the other algae can out compete it. If your not already, try feeding less and just keep up on the cleaning.

Hope this helps.

[SPAM]

Wouldn't a glass or acrylic layer between the lights and water decrease how effective the lighting is? It seems to me that glass would hold more heat than acrylic also? Also, forgot to mention, that we use distilled water to do our changes, this is to avoid the phosphates, shoud we change this?

[bongobrian]

I just wanted to add that distilled water still contains phosphates. If you don't believe me, test yours! I had the same misconception for the longest time and I payed the price. Use R/O water if you can, it generally has the least amount of nutrients.