Help me understand DE filter grids.

[Thinkly]

I am somewhat confused when it comes to DE filter grids. Everything I’ve read says that grids plug up over time and need to be acid washed.

If that is the case wouldn’t it increase the pressure in the filter and decrease the return flow into the pool?

My grids were 10 years old so I just replaced them, however I’m wondering if it was necessary? I’ve just thought the last several years my water hasn’t seemed to be as clear as normal. And yes I realize there are many possible reasons for this but I don’t think it is a chemistry thing.

 

[Richard320]

The grids themselves don't do any filtering. They just support the Diatomaceous Earth (or cellulose). Picture a whole bunch of kitchen sponges piled onto a chickenwire support. Then shrink it to microscopic size. That's your filter. Even if the grids get crusted up pretty good, the openings are still much larger than the holes in the DE particles.

I've never done anything more than blast the sticky mess off my grids in the eight years I've owned it. Never soaked in acid or detergent, and my pool has really high CH levels.

Hazy water is usually chemistry. It could be low chlorine, which leads to an algae bloom, yet there's always just enough chlorine to keep it from turning green. So what you have is an endless supply of dead, bleached algae carcasses clouding the water. My pool loses some sparkle when the pH gets too high. It could be related to the high CH; who cares? Fixing the pH fixes that. So high pH or low Fc can lead to haziness.

I've also noticed that if I get lazy (and we all do) about brushing, when I do brush, it gets a bit murky for a day or so until it can filter out. You'd think that dust would settle out on the floor, but it doesn't. Just like it sticks to vertical window panes, and not just horizontal surfaces, in the house. So if your chemistry is good, maybe you need to brush more.