400 Watt & clams?

[csufman]

I am putting a 400 watt 20000K mh on my 40 gallon reef tank. Will this be adaquate to have a couple of clams? It will be one bulb in a diy canopy with a parabolic reflector aout 8 inches above the water.

[Physh1]

That is more than enough light. I would probably raise it up to 10-12 inches. You don't want to burn the poor suckers. That other than that just make sure your calc and alk levels are good and probably a phyto supplement would be good....like dt's or similiar..

Cameron