ATO diluting salinity

[gregzz4]

Is your overflow plumbing able to handle full flow from your return pump ?
I ask as I noticed during testing mine that there is a correlation between my sump level and my overflow level. Not just the actual levels, but the water level in the overflow affects drainage speed and so on.
I am wondering;
If your overflow can handle full flow maybe it will help you stabilize the whole setup ?
Good luck