75 gal - 250w MH tank owners

miami13 · 01-25-2004, 10:21 PM

Just wondering how you go about keeping your tank temp in check (minus a chiller). Do canopy fans keep you cool enough in the summer? I'm having troubles with my 175w ballast and am tempted to use this as an excuse for an upgrade but am concerned about temperature control. I feel as though I'm somewhat borderline with my 175's. I'm just trying to maximize as much light as I can responsibly mantain. Anyone have any guesses how many degress I'd jump by adding the 250's ?

My tank is a standard AGA RR75 - aprox 20 inches in height

Thanks in advance...

Jeremy1973 · 01-25-2004, 10:23 PM

I have a 75, with 2 250W MH. The bulbs are about 10 inches from the water. The back of my canopy is open, and I have two wal-mart clip on fans there. My temp only gets to about 80.5 degrees at most.

miami13 · 01-25-2004, 10:39 PM

thanks Jeremy - I just measured and from the center of my bulbs to the surface is right at 9 inches and my canopy is open in the back as well. I have two 4 inch fans blowing across my lighting now. Maybe it won't be so bad. My other thought was to have the 175's repaired and lower my bulbs from 14000k to 10000k for a "whiter" look and invest in a pair of nice reflectors. I've never had or seen reflectors in action so I'm sure to what extent they effect light intensity.

thanks again

adrianleewelch · 01-25-2004, 11:09 PM

I have 400s on my 75, canopy is open in back, I siliconed two huge radio shack fans onto my center brace, and it stays at 81, and thats with a 9 hour photoperiod, the tank is at 79 already with all the pumps, so only a 2 degree difference in 9 hrs isnt too bad. I do lose about 5 gallons a day in evaporation, but I have a 40g sump and 29g fuge. As far as reflectors go, I bought a sheet of aluminum at lowes for $40 and took it to my buddy who is a car painter, he polished it with 2000 grit wet/dry and it is a mirror image, and lots cheaper than some reflectors...

SouthernReefer · 01-26-2004, 07:23 AM

i have a 75gl with dual 250 mh. i have my light suspended over my tank with metal brackets, and no top or hood. the only fans are built into the light fixture.

MiddletonMark · 01-26-2004, 09:14 AM

Having gone from a basic reflector with 2 x 175w on my 58 ... to a PFO parallel ... all I can say is a good reflector does a LOT for increasing light. Better spread, much brighter ... had a couple corals react adversely to the light increase [had to move them to my other reef tank].
IMO spring for one ... why not use your power bill more efficiently?

miami13 · 01-26-2004, 11:14 AM

Thanks all, it seems like the 250's are defineitly doable. Beyond the responses here I've been reading where quite a few make it work.
I think my first step is going to be getting an estimate on ballast repair - if repairing the 175's is reasonable I'm going to take up Mark's advise and get a pair of good reflectors and see the difference they can make before changing everything out. Thanks again and Happy Monday !

MiddletonMark · 01-26-2004, 11:23 AM

For reflectors, check out Sanjay Joshi's article in March 2003 www.advancedaquarist.com on the different Mogul reflectors.

I went with the PFO parallel ... but read it and decide for yourself. IMO there is a fair difference between reflectors ...