View Full Version : JBJ chiller - how long should it take to cool the tank down?

03/08/2010, 07:24 PM
I have a 3 week old 1/3 HP JBJ chiller on my 150G DT. I was thinking it would only take 5-10 minutes to cool my tank down 1-2 degrees but it takes 30-40 minutes. Is this normal? I have a Ehiem compact 5000 return pump and it goes through the chiller and UV light... Is my flow rate to slow? woudlnt it freeze up if it was?

03/08/2010, 10:34 PM
Specs on that pump state 2500-5000 l/h...is it wide open and what are you running (ie. lighting, skimmer...etc.). I believe JBJ has a formula on there website on the proper chiller recommendation based on your setup. Also, if it is wide open wouldn't that be fast to go thru your UV??

03/08/2010, 10:46 PM
hmm...i have a 1/5 jbj on my 58g tank. When I had two velocity T4 pumps it would take about 15-20 min to cool the tank to 79 from 81 (was set at 80). It took longer if I set it at 77. It also would only stay cool for about 10min before having to kick back in. Those pumps are hot. BUT, now that I have replaced one of them, the return pump, it is soooooo much easier to keep it at 77 degrees, and it stays cool longer now.

So I guess my point is that it depends on how hot your set up runs. And for that sized tank I don't know if a 1/3hp chiller is big enough.

but yes it can take time to cool down that much water, I would be more concerned with how quickly it turns back on.

03/08/2010, 11:13 PM
ahhh.. well it doesnt coem on a lot. it just stays on for a bit when it does. i have ot set at 77 and plan opn setting it up on 78 to see if that helps. going to run a fan on the sump also to help out.

03/09/2010, 04:15 PM
I used to have a 1/5th on my 90 and it took about that long to cool down. What's the ambient temp in the room? During the summer times, it took a little longer to cool than winter time because of the ambient temp. I wouldn't be too worried about 30 - 40 min.
Also, you might want to plumb the UV before the chiller. If the UV is after the chiller, then that chilled water will just get heated up a little from going through the UV.