Cannot balance return

[Zwingman]

I have recently added a sump to my 75 gallon tank as I was previously using a canister filter. Previous to that I had an older redsea all in one that I have retired. My tank is not drilled so I purchased an eshoppes HOB overflow. I went with the 1100 which was a bit oversized however allowed for an emergency overflow which I felt was important. I also purchased the redsea 5500 return pump to keep everything moving.
I have had this setup for approximately 3 months now and I cannot for the life of me balance the system out. Not for any reliable amount of time anyway. My sump is directly below my tank and the return line distance is approximately 7’ as I brought it to the far side of my tank.
I have a gate valve on the return line and my main drain line feeding into my ReefMat. When I get the siphon going I dialled the gate on the drain to allow it to drain silently. I then adjusted the return pump speed until it was close to balanced and used the gate valve on the return line to try and fine tune. The issue I have is my display tank level will be consistent all day with my pump running at 40%, my ato going off now and then in the sump and everything seems great. Then overnight the ato reservoir will empty and my display tank level is way higher.
I adjust the level in the display tank again but now the pump running at 35% makes the ato run constantly and wants to flood the main display. It’s like the pump speed has no consistency although I am sure it’s user error in some way, I am at a complete loss. As I write this my pump is at 30% and levels rising. I cannot have my ato on unsupervised as it runs the risk of diluting my water and I have no confidence in my setup at all if I am not constantly watching it.
Is this happening because I oversized the overflow box? Am I trying to balance the system in the wrong order? I am looking for any advice on how to get this operating smoothly as I feel like I am chasing my tail here.

 

[esquare]

I am not familiar with HOB style overflows but here are a couple of things that jump out to me;

• If you are trying to run a full siphon on the main drain to keep it quiet, it may benefit you to allow a trickle to go down the emergency to allow for variances in the return pump speed.
• My ReefMat creates variable water levels in my sump. As the fleece clogs up, the water level in the ReefMat rises until it triggers the fleece to advance which causes the water level to drop. This will be mirrored in your return chamber where I assume your ATO switch is located. This shouldn't be a large water level swing but, maybe when coupled with your return pump flow varying, it is having an affect on things.

 

[Snoopy 67]

Will the overflow run with the pump flow @ wide open ?
Find out where this WILL happen & leave it there.
Unless the pump is way oversized the roller mat should handle it without any valve.
Silence is something to overlook until everything else is solved.
As stated above, there can be some fluctuation with water levels using a fleece roller.

 

[esquare]

Also, you may want to look up Herbie Overflows as this seems to be what you are trying to achieve.

 

[Asm481]

Sounds to me like something is maybe blocking the weir teeth to the overflow which raises the level in the display THEN the ato kicks in doing it's job then the weir clears or just finds it's new level. I have no experience with valves in the drains. I have always used durso overflows. I have used hang on back overflows and know the flow wants to be fast enough to prevent bubbles in the u tube. Sometimes I removed one of the u tubes to keep flow matched with a tank or pump.

 

[thedon986]

I always have some water going down the emergency drain. I found it impossible to balance, even with my non-siphon overflow due to power head speeds ramping up and down and also return pump slowing over time.

 

[stoney7713]

You said the height in the display is varying correct?

I've ran a couple HOB overflows before, I had to replace the U tube on one because after decades of use it developed a pinhole leak in the top.

I replaced them with slightly different u tubes and it was like they were not keeping up despite being a few mm larger.

One thing that I tried and worked was slipping a small piece of PVC beneath the u tubes. By raising the u tube it increases the flow rate from the weir to the overflow box.

Raise your U tube maybe 1/4 to 1/2 inch and see if that increases the flow. You should be able to simply pick it up slightly and notice an immediate difference if that is the problem.

 

[mfinn]

I have not used a herbie setup on a hang-on-back overflow before, but because of the u-tubes in the mix, maybe they don't work the same as a drilled tank with a herbie design? It might need to be run wide open ( drains) . I'm not sure, hopefully someone will correct me on this if I'm wrong.
Since the return pump has a controller, I would open the valve all the way in the return piping and use the controller to regulate the amount of water the pump is moving.

 

[Zwingman]

The ReefMat varying the levels in my sump is not the issue. I did account for that, it’s the fact the return line is out performing the siphon but on an inconsistent basis. However I am at a loss and appreciate all the advice. I did just lift the u tubes and did. Price and improvement right away. Now the trick will be if I can sync the return with it and will it stay consistent.

I will see how high I can run my pump however with a max gph of 1450 and my tank only being a 75g, I am hesitant to turn over my water that often.

 

[Zwingman]

I have not used a herbie setup on a hang-on-back overflow before, but because of the u-tubes in the mix, maybe they don't work the same as a drilled tank with a herbie design? It might need to be run wide open ( drains) . I'm not sure, hopefully someone will correct me on this if I'm wrong.
Since the return pump has a controller, I would open the valve all the way in the return piping and use the controller to regulate the amount of water the pump is moving.

The way I looked at it was, the size down from the hob I got had a single drain line only and no chance for and herbie design. I thought my method would be acting the same but I could implement an emergency overflow. However you could be right, I’m not sure. The smaller model only has a single u tube where the one I’m running has two. Although I would have thought this would drain my display faster if anything. Which is not the issue I’m running into.

 

[Neocold]

I am running a Eshopps PF-1200 HOB with my 75 gallon tank and a custom 29G sump with a Hygger 24V DC 2650 GPH return pump.

In order to balance my water, I have to run the pump at 30% (I know super oversized) and adjust the valve on the main overflow drain (one setup as a primary drain the other setup as an emergency overflow).

I have noticed that if not set right the U tubes in the overflow can touch the bottom of the black box inside the tank and restrict flow. You may look at either trimming that side slightly or putting a small something under the peak of the U on the tank rim to hold them up a little, maybe that is your issue with the inconsistency?

 

[Snoopy 67]

The model 1100 box supports a Bean Animal overflow system @ 1100 GPH.
More than capable, are you running this configuration?
What is your return line diameter?

 

[MoshJosh]

A note about the U tubes and raising them off the bottom, you can cut both the ends of the tube at 45 degree angels and should achieve the same effect as raising the tube:

 

[Uncle99]

Your description of the problem sounds like your pushing too much water,

With gates fully open, Start at basically zero speed and move up 1% until water just starts to flow down the overflow.

Stop at this point and adjust the gate if noisy.

Had this same problem for months on end.

In my case I can run at 60% but it does what you describe

At 30% I’ve never had the problem again in 2 years, however my turnover is a bit slower than desired