metal halide heat/evaporation

[Patrick Bateman]

I'm thinking of putting a 150 metal halide unit with 2x24 t5ho actinics over a 20 long. I will have a 20 H sump as well.

How much evap/heat do you think this will create if I use mounting legs over an open top. Will it be too much to deal with?

[huseman808]

You should be fine. I use a 150MH with 2x14t5ho. Temp isnt an issue for me and I evaporate about 3 gallons every week-week and a half. 26 gal

[saltysailor2329]

Well I have a 125g with 3 x 250 and 2 x 150 MH lights running for 8 hours hung about 8" above water level. I run a little desk fan over the return section that keeps temp in check and I evaporate about 3 - 4 gallons per day. Much more than I anticipated, but good for when I add my two part doser to the ATO 10g tank.