Float Valve sticking - ATO ideas?

[GuppyHJD]

My ATO is as basic as I could make it...My RODI fills my ATO container each morning at 10am with a simple float valve stopping the flow (and for redundancy my RODI only runs for 10 minutes to fill the container). The float valves are the BRS white plastic valves.

Below my ATO container in my sump are TWO basic float valves that are fed by gravity from the ATO container. The two bottom valves get stuck UP, preventing water into my sump. I had one float valve and when it would randomly get stuck, I added the second. Now both got stuck UP. I have taken them apart and cleaned several times. I am wondering what are better ways to make this work?

I have considered adding weights to the floats?
I have considered the gravity feed is not strong enough, and should add a small pump?

I like the simplicity of the setup but perhaps an electric ATO is in the future?

 

[Sean Clark]

Have you tried removing it and cleaning it with citric acid or vinegar?

 

[GuppyHJD]

Have you tried removing it and cleaning it with citric acid or vinegar?

When I have cleaned them, I have used citric acid and a toothbrush

 

[Sean Clark]

When I have cleaned them, I have used citric acid and a toothbrush

Perhaps it is just time to replace them then. I would stick with the float valve setup you already have, nice and simple, unless you want to go with an electronic one.