Metal Halide tinkering

[trophicide]

I finally got my 125g lighting the way I want it. I have messed with just about all the different kinds of fluorecent lighting. I got bored with fluorecent and bought a simple 100w MH floodlight from Homer Depot. I gutted it, and rewired it. I mounted the ballast in the stand. I made a housing for the bulb and its attatched to 1/4 piece of glass. Fired it up coupled with a 100w flourecent PC bulb made by Fluorex that has a E39 mogul type base on my wifes heavily planted 55g. WOW I was amazed how much O2 the plants were producing. Looked like there was a bubble wand hiding somewhere. I was tempted to throw a bag of crab boil in the tank with her cherry shrimp. So how much lighting is too much? She does have several different plants that require alot of light. Would I be peeing in the wind if I added more lighting? The outside of the MH housing was running at a temp of about 285. Would it be ok to add a fan on the housing and blow air across the bulb to cool things down a little? I saw somewhere that MH has to have a special glass to block to UV rays because it can hurt the plants and fish. Any truth in that or will any glass do? I noticed there are different types of MH bulbs (like different connections). Which one is used most by aquarium? Any more info on MH would be much appreciated.

[oneoffcustom]

If the metal halide bulb is double ended or HQI, then you need a uv protected glass under the bulb. If the bulb is SE, then you need no glass under the bulb. As far as plants go 3000k to 6500k are great, if you can find the bulbs to suffice. I looked into the home depot halides, but found that no aquarium bulb manufactors make 100w bulbs. You mostly only see 70w, 150w, 250w, and 400w. These wattage bulbs can be found in all different color temps for the aquarium hobby. As far as the fan, that would be almost mandatory with a halide, cause the heat of them is intense and can swing your temp by several degrees. I would add two good sized fans on each end of canopy one pulling air in and blowing across while the other side pulls air out of canopy. You may also consider running them only a couple of hours a day. In a planted tank you make get major algae issues, i know i did. As far as intinsity, you may end up over working your plants if you are not running co2. High light + high co2= high tech planted tank. Without one or the other you will over work plants in their photosynthesis. Halides are awesome cause you get a great shimmer effect, but IMO, i believe them to be overkill in the fresh water hobby. I also believe that with new breakthroughs in aquarium lighting, there are just to many other choices that dont deal with heat, and power consumption. But in a reef setting they are boss.

[blacksmith37]

I mounted a 400W at one end (avoid center brace) of a 125 salt. A few years ago I converted to fresh and have not used the MH. I guess I will fire it up for a couple hours/day. Especially in cooler weather (I have a fan that blows through the hood and into the attic).
I don't worry about UV as it dosen't take much to slow it down to visible light. I have a mogul base , I think they always have a glass envelope over the MH bulb , I believe that is enough to not worry about UV. The bulb is a few inches above the water and when it was salt I removed the bulb and rinsed it to remove salt- sodium will damage glass and quartz at high temp.