HQI Ballast/Bulb question

[cprdnick]

I recently purchased a MH fixture with a 150W MH and 2 x 14 w T5 actinics. I haven't installed it on my tank yet since I just got it in, but i have had thoughts that maybe a 150W MH is too much for my 18 Gal. Since the ballast is set up for 150 watts, does that mean i HAVE to use a 150 watt bulb, or can I use a lower wattage HQI bulb? I was thinking maybe I could just put a 75 watt HQI in its place if I decided the 150 watt was too much for my tank. Thoughts?

 

[acrylic51]

No you can't use a lower wattage bulb. The light should still be workable though.

 

[cprdnick]

I've had it on for the last 4 hours, i think i'm sunburnt, and i'm gonna have to get a fan to keep the tanks temp down i think. other than that, i've never seen this tank look SO good.

 

[acrylic51]

How high above the tank is it mounted? If anything take it up higher and try the fan.

 

[cprdnick]

the mounting legs it came with have it about 8 inches above the rim of the tank. I pulled the heater last night to let the tank cool off to room temp (still only water in it for testing equipment). its 11:02 a.m. right now, I turned on the light at 8:30 ish a.m. and the tank has only reach 75 degrees from the original 73. I'll leave it like that all day to see what it would do on a 9 hour cycle, but I think it's gonna be ok. I didn't put the cooling fan for the light on until after i posted last night, so i think thats helping the situation.