Stand pipe not keeping up with return pump

D

David Gibson

Premium Member
After three days of waiting on my RO/DI filter to do its work, I finally had enough water to completely fill my tank and sump. Excited to have everything running, I fired up the system and watched the overflow fill and start coursing through the sump.

Had a small bump when the new stand pipe I made in the overflow started acting like a toilet bowl. I took then endcap off the top and increased the size of the air hole a little and capped it back off again. Seemed to start behaving a lot better at that point.

Then... I ran into a big bump. My overflow started to fill up past the elbow. As I watched it, it creeped higher and higher. When it was even with the water in the display tank, I cut the return pump and it drained back down to the elbow.

I took the end cap off completely from the top of the stand pipe and turned the pumps back on. Again, it slowly filled up completely to where it was draining into the non-capped end, so I shut it down again.

I have a Mag 9.5 for a return pump, 1" spa flex hose to the bulkhead (which I think is a 1" bulkhead) and 3/4" pipe to a Y loc-line return nozzle. The overflow is a 1" PVC stand pipe I made to what looks like a 1 1/4" bulkhead, then a 1" PVC pipe straight down into the sump. I have ball valves on both drain and return.

I'm thinking that the drain just can't keep up with the return pump. Is there anything I can try short of partially closing the ball valve on the return to decrease the flow?
 
If the return pump is filling the tank faster than the overflows can handle, the only option is a smaller pump or put a ball valve on the outlet side of the pump and close it a little.
 
A 1" bulkhead will drain about 800gph... give or take. Some handle a bit more, some a bit less. As was mentioned, drop the flow into the tank by dialing back the pump.

What size tank do you have? If you are putting 800gph through the tank, that is enough for a 200G tank, so if you have anything smaller than say a 150, you are using too big a pump and/or allowing too much flow into it.

Use powerheads to move water inside the tank, all a return pump does is fill the tank up.. thats its only purpose, it should not be used for flow inside the tank.
 
It's a 58 gallon tank (36L x 18W x 20H). I do have a ball valve on the outlet side of the return pump, so I'll dial that back.

I appreciate the advice.
 
@Gramalkin wrote:
It's a 58 gallon tank (36L x 18W x 20H). I do have a ball valve on the outlet side of the return pump said:
You've got way too big a pump on it then... A Mag 3 would be fine, Mag 5 dialed back a little. A mag 9 is way too much and if you dial it back too much you may end up wearing it out faster or having it vibrate.
Click to expand...
 
I have a Mag 5 on my 30 cube with a one inch drain and its about perfect, If you decide to sell the Mag 9 and down grade, let me know, i am interested. I am looking for a mag 7 or a mag 9 for a close loop.
 
Luckily I had a Mag 5 on my skimmer, so I swapped it out. The Mag 9 has a 3/4" connection, and the Mag 5 has 1/2", so I had to re-do my connection, so I ended up taking the opportunity to removing the 1" spa flex and switched to 3/4" PVC hard lined.

All told, it works like a charm now. Even with the ball valve open fully.

Malo, I'll PM you. I don't really have anything that I would need the Mag 9.5 for, so I'd be willing to let it go.
 
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