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

1990jpyj

Member
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

Active Member
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.
 
J

justin podolan

Guest
I thought it was 8 in. or more

i dont have mh so i am no help
 

1990jpyj

Member
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
 

1990jpyj

Member
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.
 

meowzer

Moderator
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

Member
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
 
Top