Overflow Return line very slow

I just set up a sump/refug. its an 20 gallon tank. I'm using a mag5 pump going up around 4 feet. this should give me somewhere around 400gph max input. I have 1" bulkheads in and out of the tank. They are placed in each top corner roughly 2 inches from the top and side. Here is my problem, it seems that the return line to the sump doesn't have very good gph the 1" bulk head is connected to flex pipe which goes directly into the sump. When I pull the hose out of the sump and watch it its capacity around 1/3 of the hose. Im going to add a external durso tomorrow however from my reading this will not increase the flow. Anyone have suggestions on why the out flow to the sump is low? Any advice on how to get water out. The 1" bulkhead should handle up to 600gph but I'm sure I'm not even close to that I'm thinking there may not be a siphon, which i wouldn't mind. Could the return hose be to large?

 

Well, the smaller pumps are going to lose more pressure (percentage wise) compared to their larger counterparts at 5'. Your Mag 5 will only give out about 300GPH at 4'. Around 250GPH at 5'. Now, these numbers are not big. So the flow coming out of a 1 ID pipe is not going to feel like much.

 

You are right - I guess the problem is it is not draining at the rate at which it should, I sat up late last night thinking about what is going on and I have one idea, My overflow to the sump drain pipe is to large, larger than the 1" bulkhead, thus not creating a siphon and not maximizing the return gph and causing the tank to fill up faster than the return can remove it. What do ya think?

 

kinda having a hard time with comparing cause i use dual 3 in bulkheads. correct me if im wrong but i think john was saying that even if your overflow can support 600 gph, if your return pump is only pumping 250 gph into your tank, thats all thats going to come thru your overflow is 250gph. a sign that your overflow bulkhead, lines were not sufficient would be water backing up in your display tank

 

right - my tank will overflow, this is my case. I have done some research and found I need some sort of siphon to increase the outflow, either using a durso or some other device. I was wondering what is the best system for tanks with drilled bulkheads for getting the water out of the tank? I was thing about a external durso, however i'm having issues creating it as there seems to be lack of documentation on it. So in general what are people using with back drilled tanks to get the water out and to the sump?

 

Syphons will maximize the amount of water going down because there is no air in the line. You could always do what I did on my 55. Increase the return to a 1.5 inch line. It keeps up with my Quietone 3000 with no problem.

 

Dose that mean you have a 1.5 inch bulk head overflow with a 1" return?

 

Most of the overflow lines I've read about are 1.25 to 1.5. IIRC my 300 gph rated overflow recommended 1.25" to keep the 300, smaller and it dropped. You may want to try going up to 1.25 or 1.5.

Also, a lot of the durso/cj designs I've seen use a 1/4" hole drilled with a piece of airline hose inserted to allow air inspiration to prevent (noisy) siphons.

 

Perfect - I solved the problem. So heres what was going on...
The pump meg 5 on a 1" bulk head has the ability to push more into the tank then a 1" overflow can return, simple as that. So in my design of the sump I was told to put a ball valve on the pump back to the sump (just for this case) I turned it down just a tad and everything seems to be working perfectly. Im not maxing out the pump but thats ok. The other solution would be to add another bulkhead for the overflow.

I also added a tee valve to the overflow and use a durso type air intake. If I plug the hole for the air it makes a little difference in the sound. However it is worth doing. With this setup I dont believe I have much of a siphon as with out the durso it gurgles very little.

Another note it seem people think a 1" bulkhead can get up to 500-600 gph, I believe this is only possible it you use a strong siphon which with a bulkhead on the back of the tank near the top you are not going to achieve.

Thanks for all the advice, Im such a rookie at this! Btw my coral has been closed for weeks, and I pointed the return at them and they started to come back to life. OMG Just when every thing seems to be going wrong it turns around, and now I can tell my wife I knew what I was doing all along.