are 2 400w mh too much..

i dont know much about MH but i think you should have them higher off the tank...

someone else will chime in with the good info soon...

 

what type of corals you plan on doing but at that spacing i would say pry to much

 

that doesnt sound like too much to me, i would keep em at least 8 inches above the water, possibly 12 to spread the light out a little bit since you only have two.

if these were say 10k bulbs you would have to probably acclimate new corals to the intensity, but being they are 14k bulbs they arent gonna be real high par, someone will correct me here if im wrong but 14k bulbs kinda suck unless you buy either the iwasakis or ushios, i might be wrong with that statement.

if you can change ballasts i would change the bulbs instead and go to a 20k bulb. im not sure but some 20k 400 watt bulbs put out decent par and you wouldnt need any supplimentation for a blue look. im pretty sure waverz is running 400 watt 20k bulbs and he gets good growth with them.

i would definately stick with the 400s because you might at some point want a bigger tank and 400s would do well on bigger tanks.

youll get plenty of feedback here.

 

I agree with fnvarner, it depends on the corals you keep. Another considerations is heat. 400W MH puts out a lot more heat than 250W MH. If you only have a 55 with a small sump, it's going to heat up your tank drastically during your photoperiod. The other option is to hang them up a lot higher than you normally would. Then it would be inefficient so my opinion is to go with the 250W's if you can.

 

Posted By slovan on 01/01/2008 4:10 PM
I agree with fnvarner, it depends on the corals you keep. Another considerations is heat. 400W MH puts out a lot more heat than 250W MH. If you only have a 55 with a small sump, it's going to heat up your tank drastically during your photoperiod. The other option is to hang them up a lot higher than you normally would. Then it would be inefficient so my opinion is to go with the 250W's if you can.
ahh good point on heat, big consideration.
yep you better go with 250s.

 

When I was new to keeping corals I initially put 2 400w bulbs over a 75, plumbed in with a 55 gallon refugium, and had a 6-8 degree swing in temp every day.

250s will be plenty of light in a 55 gallon, without much of the heat problem. In my own experience 400s are overkill on any tank that is less than two feet deep. I'm not sure 400s are even necessary on my 120 now.

400s are unnecessary and will probably be detrimental to a 55 gallon system.

Don't forget, also, that going from 250s to 400s jumps your electric bill 60%. That adds up.