Heating effects of Metal Hallide lights

[wahboy]

Hello everyone,

I am currently using T5 lighting for my freshwater planted tank.

The total power of the T5 lamp is 156W (4 X 39W). The water does get a little warm at the end of the day.

Right now, I am contemplating using a 150W MH lamp because I like the rippling effect created by MH lights.

Will the 150W MH lamp heat up the tank more than 156W T5 lights? Comparing the wattage of the two kinds of light, the MH lamp should heat up the tank less, am I right? But I have read that MH light produces a lot of heat energy and heats up the tank easily.

Does anyone use Arcadia light sets? Arcadia's OT2 over the tank luminaire looks so good but does anyone know the price? Their series 4 pendant looks good too-- MH and T5 light all in 1.

All help is appreciated,
Wahboy

[Fuzzy]

How big is your tank, and what is its ambient temperature at present?

Are you running a chiller? In my experience, even if the MH is fan cooled, the radiant heat will build up fairly rapidly in the water.

I was running a 150w 20k double ended MH about 4cm over a 28 gallon tank (it was an integrated marine nano tank) the tank temps could soar up to 33C with ambient temps around 28C, needed a chiller for the tank.