MH for a 70gal

[xaphann]

Hi
I am looking at changing my current step to MH. Currently running 2 actinic and 2 10k T5. The depth from water top to bottom 18inchs. Right now looking at getting a Mogul 400 Watt 20000K. I want to keep more coral in the tank.
My question is for my setup can I get away with one MH or do I need more? If more then how many?
thanks

 

[culp]

it would be a waste of money to have 400 metal halide on a tank that is only 18" go with a 250 watt set up

 

[premilove]

175-250watts. you could probably get away with 150watts, but your options for coral will be limited..

 

[premilove]

oh and if you have a center brace, id try to get a fixture with 2 MH bulbs.. i think you could do 2x150s sicne 150watts can reach 20 inches deep..but then again you are probably going to have a fixture that is sitting on mounting legs or that is more than 2 inches off the water surface. look for some 2x175s..2x250s might be over kill and you would def need a chiller/cooling fan..

 

[xaphann]

Ok, so 400W is bit of an over kill. Just so you know it would be mounted to a custom hood. This means that light would actually be 12inchs from the water (did this for heat reasons).
Is the one 20k enough color spectrum? From what I have read it seems to be but would like to make sure.
Also the ballast I was thinking of going with is BlueLine E-Ballast. Any red flags?

 

[fanker]

run 2 more t-5s u can keep what ever u want

 

[rs1831]

Isn't a 70 gallon tank 25 inches top to bottom? I would go with 2x250's or a 400 with t-5's.