Question about relationship between return pump selection, and chiller

[rocknut]

I am about a month away from getting my new tank up and running, and am in the final stages of equipment selection. The tank is right around 115 gallons, and the sump is a 29 gallon tank so I’m figuring total water volume is probably between 125-130 gallons. I got a 1/4hp Current USA Prime Tower chiller, and had already purchased a Mag 12 pump to use as a return. After looking over the manual for the chiller, it turns out that the maximum flow rate for the chiller is 600 GPH. Even after head loss, the Mag 12 will still push around 900 GPH. At this point it looks like I will have to use the Mag 7 pump that I already had for my smaller tank, but doesn’t that seem like a really small return pump for a tank of this size? I’m worried about not having enough turnover going to the sump (and more importantly the skimmer) if I go with the smaller Mag pump. Any opinions on this? I have carefully selected all the equipment for this tank over the last year, and don’t want to make a bad choice now and screw the whole thing up :)

Thanks in advance!

[just dave]

Use second pump to supply the chiller on its own circuit. This way when you need to sevice the chiller you can do so without shutting down the main system.

[smcdonn]

I would also recomend using a second pump to supply the chiller. It seems like a catch 22 since your adding heat with another pump but that would probably be the best route. The chillers heat exchanger will not work at peak efficiency if your pumping water through it too fast.

[rocknut]

That sounds good. So I could use a Mag 5 for the chiller, and then my Mag 7 to return water straight to the main tank. Something like that?