40g breeder question
 

Was wondering how many inches off of the water should I go for 2 250w mh. Probably 10-14k.

A lot of variables there. Most important will be 1) what you're keeping 2) what reflector and 3) how big of a chillier or what cooling plans do you have.

Will be keeping mostly sps. With a couple of lps, and zoos mixed in. No chiller as of now. (will use 4 inch fans), and regular stock reflector that came with my lights. Maybe someday switch to Lumenarcs, but for the time being, just the reflectors that I have now.

Assuming you can adjust the height hopefully, I'd start them out decently high (10-12"). Give new frags a decent amount of time to acclimate to the light by starting them out lower in the tank. As time goes on and if you aren't having any bleaching issues, start to drop them SLOWLY.

Again, kind of dependent on the bulb, PAR, and the reflector you're using.

Why are you using 250's instead of 150's?

Had them left over from my 45.