Overflow box not flowing (now flowing)

Put up a pic of your set up or detail the way it's plumbed from the return pump to the return exit and the overflow bulkhead to the sump.

 

I understand what your saying, but quite frankly it has nothing to do with the return pump. I tested the flow rate by allowing the overflow box to flow into a bucket while adding water to the display tank to compensate. The flow rate directly into the bucket (which doesn't involve a return pump) was about 20gph.

I am using tubing that was not supplied with the overflow box so my new theory is that my tubing is just too narrow, but again, the flow rate is lower than what it should be for that diameter hose. I will try the correct size hose and see if that changes things. Thanks for the replies.

 

Well now this has me worried. I'm about to go out and buy a hose that is a wider diameter but from what you say it sounds like that isn't going to help anything. The U tube is completely free of air bubbles. Also, there is no restriction on the tube going from the overflow box to the sump, it is just an open, clear line.

I really have no idea what the problem is now... I will try to get a pic up soon.

 

Important question, what's the water level in your tank, from top how many inches is the water level?

 

Well I just did an experiment with the box using a 5 gal bucket and a garden hose. No attachments, no pumps, no restrictions of any kind, and my result was a half gallon (1/2 gal) of water in 60 seconds. This works out to roughly 30gph which is clearly nowhere near what it should be. I removed the PVC piping and I even removed the foam cylinder. I even removed the foam from the U tube.

The way this experiment went, there couldn't possibly be any less restriction, there was absolutely nothing blocking anything.

I'm perplexed.

Also, just a side question, are the Eshopp overflows supposed to come with a drainage hose? Mine didn't come with one, and the website doesn't mention it, but the LFS told me that they do.

 

Actually it does. Your overflow siphon will only flow as quickly as you're pumping water in to the tank (up to a certain point where the PF-300 can't keep up, but that's probably higher than your return pump can even flow).

Have you tried turning up the flow on your return pump? Is the overflow box able to keep up or does the tank's water level keep rising?

Obviously your 3/4" tubing will flow less than a 1" tube would, but it's not going to restrict it much in your application and certainly shouldn't be what's slowing it down to 20gph.

BTW I have a PF-300 w/1" vinyl tubing and a Quiet One 2200 return pump w/~400gph at my head height.

 

My water level sits about 1 1/4 inches below the highest point of the tank frame.

 

When I allow the pump to run at maximum pressure the display tank quickly fills with water. So the overflow box is indeed not keeping up for some reason. The problem here is that my overflow box is not flowing at a high enough rate.

Again, I understand what you are saying, and I have ruled that out as an issue.

 

There is no drain hose that comes with the overflow. Eshopps sells a flex hose kit on the side.

When you tried turning up your return pump did you have those black prefilters installed in the overflow? I've found those can be very restrictive and if they're both in there my pf-300 can't keep up with my return. The small filter definately should NOT be in the u-tube. Try removing all of that stuff (the pvc pipe is okay to have in there) and try turning up the return flow again.

I spent quite a while getting mine tuned for good flow and very low noise level. I'll post a picture when I get home of how I did it.

 

EDIT: I think I solved the problem. I removed all the foam (including inside the U tube) and all of a sudden the flow is greatly increased. Thank you for all your help. I might be back but I think I got it. Thanks again!!