MH generating too much heat

[miktrav]

Hello guys,

My175 w dual MH unit appears to be generating too much heat. The tank temp shot up to 90 yesterday. I'm thinking of building another top for my DIY hood and purchasing an ICECAP 660 DIY kit on Saturday. Then I can swap that out during the winter or just getting rid of the MH and sticking with the VHO. Is this a good idea? I don't want to have to spend $600 for a chiller so can someone suggest something? I thought that I could get by on the MH heating issue by having an open back hood and no glass top to trap the heat. What other options do I have? How are you guys cooling your tanks?

Mike

[Bio]

Mike,

I'm not big on chillers either...

The easiest way is a fan across the sump or if no sump across the tank....

Although this will increase the evap rate quite substantially it will provide relief for your tank...

[miktrav]

I'm going to try the fan today. If that doesn't work I'll move the tank down to the basement where it's a lot cooler.


Thanks,

Mike

[Aquariust]

water naturally looses heat by evaporation.

[gmh320]

Mike,
Besides the fan that normally blows across the tank to cool 2-250 HQI MH, I've been using an additional fan this week due to the sweltering weather. This fan and the central AC set to 76 during the day, keeps the tank temp around 79 F.
Greg

[miktrav]

Hello guys,

A quick update. Yesterday after reading the suggestions I went to Odd Job and bought a clip on fan for $5. To day I got home and the room temp is 86 the tank temp is 80. Gotta love evaporative cooling. Now I don't have to move the tank or splurge for more lights unless I want to get rid of the NO actinic and put in VHO actinic instead. Thanks for the advice.

Mike

[Rovert]

On a vector to this tank heat issue, has anyone tried a strategy of reducing the tank heater temperatures to compensate for the increase that occurs during the day from the lighting?

IOW, assuming that during the day, your tank gains 6 degrees, if your heaters are set to 78, you're up to 84 by the time the lights go off. If you back off the heaters to 74, wouldn't that mean that your tank would top off somewhere around 80?

Yes, 74 is lower than normal, but getting back to comments made at MACNA, bleaching studies show that corals survive lower temperature limits better than high temperatures. Since the lights SLOWLY warm the tank during the day, it doesn't present a sudden change in temperature.

Any thoughts?

[katspaw]

Rovert,
That sounds very logical, and I am sure in an air conditioned room it would more than likely work. I run A/C at work during the day, but the prices to A/C in all the offices ( more in back that the club hasn't seen ) It isn't economical for me to leave the A/C running 24/7. So my heaters will never kick on until tank temp drops below 78 degrees. And just like the high heat does damage to the reef, so does not enough heat. I have read a great deal on the subject, and I have studied ways of building my own chiller. Something I had put on the back shelf lately do to family business needing my attention. But I know that I can build a chiller exactly like the CSL chiller for kess than a $1000.00 to go on my 255 gallon ( 1 1/2 hp ). And it will more than likely work on Malcolm's 300. So the cost of this chiller would go down as the size of the hp's or size of the tank decrease. Just thought I would make the suggestion if anyone was interested.

Tracey