Overflow ?'s

[Glenn]

I'm putting an overflow on my 20L to send water to a 10gal. fuge. My turnover in the fuge will only be btween 3-5 gph. My questions are: Will this low flow break the siphon of the overflow? What kind of overflow should I get (U-tube or CPR). Thanks, Glenn

[DeskJockey]

Well I use a u-tube on my overflow box and I adjusted the flow from the return pump (maxi-jet) so it still had good flow but not too much. I have an aquaglobe in the main tank and the two create too much movement if I leave them wide open. You might notice micro bubbles get trapped at the top of the u-tube so I would check it when ever you feed your fish or whatnot. As the micro bubbles collect (like over a few days) it can become a big problem. Just keep some air-line tubing handy so you can restart the siphon with no bubbles.

[Glenn]

DJ: The U-tube seems to be more time tested and more reliable. I have read of some people loosing siphon with the CPR overflow. My main concern is that it will loose suction with such a low amount of flow (aprox. 30-50 gph). Guess I will just have to get one and install a valve to regulate flow. Seems I will have to do some experimenting. X)

[DeskJockey]

Well if you go with a maxi-jet 600 I can say you wont have problems keeping the siphon. Same thing Im doing and thats the least of my worries, just have to keep an eye on those micro bubbles.

[DeskJockey]

I dont have any micro bubbles coming from the fug but when the water falls through the teeth on the internal box it creates bubbles. And if a few get trapped they trap more, and more, and more........