Filter socks are good as long as there kept clean otherwise I think there a PITA. I run an ATO using the double float system into the return pump area, which gives me constant level accuracy for the pump.
I use filter floss in my bubble trap area just before the return pump chamber for cleaning and don't use socks anymore, and always trickle down the emergency overflow, It works well for me. I just maintain a clean Herbie strainer in the overflow box. :biggrin:

too much noise for me , a trickle down my emergency would drive me nuts....and i dont submerge my emergency as i like to know when its going off so i can fix it , if its submerged you may not know if the main is clogged unless its creating bubbles;)

My water level is the same level as the top of my emergency pipe so I only get a few drops down the pipe, can't even hear it at all until it starts running out faster, then I clean the herbie strainer and it's fine again.

Hey Dunc

I know you said this setup is fairly new, but could there be something in the drain ?

I have the same problem with my 'fuge from time to time. It'll climb to overflowing and I try to open it up enough to lower it. But then it just suddenly drops as if I opened it wide

I find the only way to reset it is to open it all the way to flush out whatevers in there and then I can reset it just fine. And it lasts for months after a flush

Another thing
Is your plumbing under water in the sump ? If not air in there will mess with your levels

Oh, btw, I haven't had to tune my setup since my build over 2 years ago (except if the pump strainer gets clogged), and I don't purposely run anything down the emerg

I don't run an ATO. My return section in the sump fluctuates quite a lot as I am so busy sometimes I let it get too low. I'll keep an eye on that and try to keep the level more stable and see how that influences things.

Thanks for all your input. It is very much appreciated.

Dunc

Sent from my Nexus 5 using Tapatalk

I would also consider a durso mod for the splashing and silence.

Oh
That'll be your problem right there

A couple things to try.
Where is your gate valve located? Depending on the location it can potentially trap air and cause throttling issues
Try a different return pump. You could have a bad pump that is fluctuating how much flow is going into the tank.
Try a different valve. I personally had a pvc gate that I could not keep a constant level with. I switched to a true unoin ball valve and never had another issue.
Does your drain run vertically into the sump or is it horizontally offset? Large or too level of an offset can trap air causing fluctuation in the siphon.
Can you put up a couple more pics of the plumbing as it leaves the bottom of the overflow box and enters the sump. I think your issue is more likely drain related vs pump related

Yup guaranteed:)

I never ran an ato either. The height of your drain comparment staying the same is more critical then return. Unless the pump begins to suck air. The weight of 4-6 inches of water varying in your return compartment is minimal @ 0.433lbs/ft but anything is possible. One more thing. Installing a valve on the outlet of your pump and throttling slightly will give a more constant flow rate too. If the pump is being held back by a valve the level fluctuation will cause less of a change in the flow rate of the pump. That is if you have a return pump with enough extra flow to throttle it.