DE Filter High Pressure

[Tim70]

I am experiencing high pressure minutes after I clean the filter. Even after acid washing. Do I just need to replace the grids? Or should I let the grids soak in acid longer?
Filter is a Pentair FNSP 48 and is about 8 years old.

 

[Jimrahbe]

Tim,

Welcome to TFP.. A Great resource for all kinds of filter issues..

I have a couple of question for you that will help us, help you figure this out..

1. What is the filter pressure when you say "high"?
2. What is the filter pressure right after you add the DE?
3. I assume it has been working ok and you just now are having this problem?
4. What does your water look like? What color is it?

If your pool is green, it will not take long to plug up a DE filter.

Thanks for posting,

Jim R.

 

[Tim70]

1. What is the filter pressure when you say "high"? 20 Psi
2. What is the filter pressure right after you add the DE? 12 psi
3. I assume it has been working ok and you just now are having this problem? I started having problems at the end of last season. I thought maybe it would fix itself over the winter.
4. What does your water look like? What color is it? Pretty clear.

I acid cleaned the filters last season. But I may have not used enough acid. This season the pool store sold me some Omni Filter and Cartridge cleaner.

 

[Jimrahbe]

Tim,

I have never personally seen a DE grid that was bad for anything but being torn and letting DE back into the pool.

I would think that if the grids were not clean, that you'd see the problem when running without DE, but maybe not???

I assume you have a single speed pump..

Do your grids "look" bad?

It can't hurt to let them soak again, but after 8 years, it would not hurt to replace them either...

Let's see if one of our other members can chime in with some better advice.

Thanks,

Jim R.

 

[Tim70]

I backwashed the filter again and added new DE. It seems to be working OK now. I guess it just had too much crud in it from opening the pool.