Herbie Overflow Have to Readjust Siphon whenever return turned off?

[rortman]

Hi Everyone,
Hoping to get a big of help with my Herbie Overflow tank. Set up it following GMAC's guidelines and the thing is deadly silent. I can lock in the siphoning really well and when it's set it's running perfect. My issue is that whenever I have to turn the return pump off to do a water change or for whatever reason it takes hours for the level in the overflow box to return to normal. If not hours I then end up pumping water into the display to bring the water level back up to the normal level (just tricking down the emergency drain).

My big concern is if my return pump is just not strong enough? I have 1" piping all around with main drain connected to a Clarisea SK5000 Roller mat. Return pump is a Jebao DCP-3000, running at 100%, through 45º elbows to about 4 feet above. Then to a VCA random flow generator nozzle. Main display is around 90g with total system volume ~120g.

Would increasing gate return pump help with this? It takes ages to fine tune again and end up always overflowing my skimmer because the sump level is just too high again.

Thanks in advance for anyone who can give a bit of advice!

 

[mann1139]

I took a quick look at that pump. Its listed at 845 gph, which would be the flow with zero height difference.

I couldn't quickly find the head/flow curve, but pumps lose quite a bit of flow to push the water 'up' the 4-6' to get back into the DT.

Make sure to get a pump that is raised for the flow you want at the head height you want. So if you are looking for 10x turnover in a 120g system, you want 1,200 gph at 5' of height.