lighting

[whiirly]

i have recently purchased a 250 watt mh with dual vho
what i would like to know is do i have to keep it off the top of the tank if i
still use my glass lids.my tank is a 110 tall 48x18x30deep
thanks
whiirly

 

[Unarce]

I've never had MH myself, but have read that they should be at least 6" from the water. Even with a glass shield. Hopefully, a MH user will reply.

 

[whiirly]

thats what i heard also but was wondering why

 

[Will C1]

why is because of the heat. put it on a table and fire it up wait 5 min and touch the outer sheild and you will see why. also you dont want a glass sheild on top of your tank it will interfere with the oxygen exchange. but i have seen mh's melt center braces so dont just lay it up there. i suspend mine from the celing 8" above the water surface.