Filter Slow Down after a few hours

[Wajda]

Hi everyone,
We cannot figure out what to do with our pool. We have an older above ground 11,000 gallon pool. The filter was a very old DE filter giving us many problems. One problem was that the flow would be strong for a while then become really low. We just bought and installed a new Intex Krystal Clear Sand filter. We set it up and got it going but the same things is happening: we have good flow for a few hours but then it really slows down badly. Things that seem relevant to me (but I am clueless): the pressure gauge is staying at zero, and the new filter returns to a strong flow if you re-circulate it or rinse it or do a full backwash. The old DE filter would do this and then it was taking many hours it to get it going again, so that is at least good. Any ideas??? Thank you.

 

[Texas Splash]

Hello and welcome! The filter sounds like it's doing what it should be - filtering and getting clogged resulting in less flow. Can you post a set of test results for us? That could help considerably.

 

[Wajda]

Hi,
As a clueless new pool owner, I am not entirely sure what you mean? Testing the water? I have the results from last night, and I'd be glad to post them. But I did add the chemicals as instructed so I assume it would look different now.

 

[Texas Splash]

Yes, it would be good for us to see your tests results as follows:
FC
CC
CYA
PH
TA
CH

These help give us clues about your water to confirm or rule-out chemical issues. In addition, please tell us how you typically chlorinate your water, and don't forget to update your signature with all of your pool and equipment info much like mine below.

- - - Updated - - -

Also, make sure to review our ABCs of Pool Water Chemistry page and save/read those Vital Links below in my signature. They will all help you tremendously.

 

[Wajda]

FC: .06
CC: .11
CYA: 2
PH: 8.4
TA: 99
CH: 183

We use chlorine pucks. But after deciding to trash the last filter, our pool sat untouched for about a week until the new one got her. Also, I put PH minus, Alkalinity Plus, Chlorine shock since this test in line with the recommendations. Need to stabilizer still.

 

[Texas Splash]

Those are some interesting results. Can you tell us where you tested those at? Home or store? If home, which test kit?

Now if those are accurate, and I'm a bit concerned about that, yes, the stabilizer needs to be at least 30 (CYA). In addition, you can increase the FC (regular bleach) to about 3 ppm.

Yes, you also need to lower the pH right away. for that we use muriatic acid - the strong stuff. You have to be safe with it, but it works fantastic and it's cheaper than those pool store products. When you need to adjust something, always refer to those links I gave you (in my sig). Avoid specialty products as much as possible.

So right now, focus on increasing the CAY to 30, increasing the FC to about 3, and lower the pH to the mid 7s. Always use the PoolMath to help.

Adding CYA:
To increase CYA via granular stabilizer, place the required amount as calculated by the Poolmath calculator into a white sock and place in the poolside skimmer basket. For those concerned about suction flow to the pump, suspending the sock near a return jet or from a floating device will also suffice. Best never to allow undissolved granules to rest directly against the pool surface. Squeeze the sock periodically to help it dissipate. Once dissolved, consider your CYA adjusted to that programmed (target) level. CYA test readings should show a rise in 24-48 hours, however some pools may experience a longer delay to fully register. Best to confirm final CYA in about 5-7 days before adding any more stabilizer/conditioner.