I'm looking to add some lighting to the sides of my tank to help fill out the illumination pattern. There are two empty areas on either side of the MH where I think I can install LEDs.

I've read a lot of this thread, but it's a bit like drinking from a firehose. So how about some advice?





Wasn't planning to replace the T-5s or 150W MH already installed. My fixture is basically empty behind one side, but has the existing ballasts on the other side.

I'm not doing SPS.

I don't think I need dimming, since I will have three different light sources I can sequence.

Not sure about optics - I'll be close to the glass on the sides, but using tight lenses might limit front-back spread.

The built-in moonlights in my fixture are expendable - I could relocate them or use a string from my AC III.

I did find a thread showing a similar upgrade to an Orbit fixture (may be the same model I have.) But build details weren't provided.

Orbit thread


I already have a soldering iron and DMM

Thanks,

Art

I'd look at raising the fixture first before diving into anything else. Raising it 4-6" will improve your coverage considerably.

I thought about that, but the higher I move the light the less my PAR.

Besides the r^2 loss, I'll be losing light from the ends of the T-5s. And for a 24" deep tank my PAR is marginal now. So I was thinking beef up the ends of the fixture instead.

I figured the risk I'm taking is that I might get color temperature variations across the tank if I don't match the MH and the LEDs. Then I'd just have to rip out the MH and redo the fixture as all LEDs.

First thing you should do is crack open the fixture and see how much space you have to work with back there. It may be as simple as attaching a heatsink to the back side of the plate so it's in the airflow of a fan, and attaching the LEDs to the front side, provided that plate is aluminum of course.