I have put many of these plastic or aluminum floats on in my life, but last 2 just will not close for whatever reason and I get slow flooding. Any other floats that u all use that u have found thst work better?

I think mine are all made by BOB. But I might have a couple that are another brand that escapes me. I feel like it was close to $100 per valve whatever it was. No matter, your issue is the seals. You can get them at any decent feed store. I buy mine from Mumme's or Lissie & Eckel. My opinion is that the hard water crusts up and causes issue and so the valve just never really shuts off. I do try to over adjust my floats as the valves age to get as much leverage on the float.

I also have "little giant" valves on a few standalone troughs. I think hard water is tougher on the pot metal and plastic versions of these. I do not think there is anything you can service or get parts for. Tractor supply might have parts. I'd tend to just replace these kind.

What style exactly of float are you working with?

I've had great luck with Watsonfloatvalve.com.

I started using Jobe brand floats several years ago and have been pleased with them.

Have you tried adding a simple RV pressure regulator to the line? I used to have the same issues on several troughs and a guy recommended them to me and it 100% solved my problem. I typically buy the brass ones and keep a spare or two in the truck. You can also buy them in a plastic version.

These have worked pretty well for me. Specifically for wildlife watering troughs, no cattle.

https://www.rubbermaidcommercial.com/material-handling/farm-garden/stock-tank-float-valve-black/

I'm 71….used the solid brass valves years ago…can't tell yall how many times I had to tap out and rethread the brass rod on those things!!

Gone to the the Jobe mentioned above as well as the Hudson model. All still require maintenance ever so often.