how high should MH's be off the tank???

[1990jpyj]

ok so i am looking for a set of MH for a 20g. i plan on building a canopy for it, so my question is how high off the tank should the MH's be? i also plan on running a cheop set of T5's for some daylight, but all retroed into the canopy.
i plan on hooking up a set of computer fans i have laying around to pull out alot of the heat.
so my only real question is how high should they be off the water?
thanks

 

[t316]

You are probably going to get a wide range of measurements on this one. Personally, my MH's are over 20", but there's a lot of them and it's a 280 gal. tank. So hopefully someone with more comparable arrangements as you will chime in.

 

[justin podolan]

I thought it was 8 in. or more

i dont have mh so i am no help

 

[1990jpyj]

i was kinda hoping for the 6-8" range so that the top doesnt look funny on it. so i gues si will wait to see what some ppl say

 

[t316]

With your setup, I think you are in the ballpark of you hopes....

 

[1990jpyj]

also another question. i plan on trying to get a small anemonie in there. i would also like some zoa's, frogspawn(if i deside to not go anem), xena, and a few softies if there is room.
so what type of bulb should i get?
i am retroing a 150w fisture in there with parts from a few different places, so i have nowhere that supplys a bulb. so i dont know what to even look for.

 

[1990jpyj]

 

[meowzer]

I just bought a mh light for my 225g..I bought one that sits on your tank (or hangs) the feet are 3"...so apparently my lights are 3" off the top of tank.

 

[kaingers]

My MH is 10" off the top of the water on my nano. There is no canopy and I have to run a fan continuously while the light is on to regulate the temp. For a 20 gallon you are going to want it to be in the range of 8-12 inches because your body of water is so small and a 150 watt MH will heat up your water quick.
If you like a bluer tint go for a 15K. If you are retro-fitting T5's in addition to the MH, go with a 10K and use actinics for the T5's