Replace sand? Water won’t clear after 6 weeks

[prarielakes2012]

Hi everyone. I’ve never posted before. I have a 10,400 g fiberglass pool, pentair pump, 24” Hayward Pro sand filter [7 years old], Pentair heater, Hayward PS8 controller for SWG with T-15 turbo cell. For past 7 years have had crystal clear water within weeks of opening using TFP SLAM method and values during pool season. However, will also throw in that in the past 7 years have gone through 3 solar covers and the little blue dots I’m sure got into the sand filter. Not sure if they backwash out, but kinda assumed they did...

After pool was closed down last season, we took off cover while bricks were being re-sealed. The brick guys used polymeric sand and a top sealer applied with a sprayer, getting into the pool. I removed as much of the chemical sealer that polymerized on top the water as I could, then put cover back on and let winter go by. Enter 2024

I opened early [4/1/24] and the water was deep forest green but no chemical residue on top. Before turning on the equipment, mega-shocked for weeks with brushing until the bottom was visible [no equipment running], vacuumed the bottom to waste, then turned on filter. Despite SLAM’ing to CC <0.5 with CYA 60, salt 3000, pH 7.5 and taking Chlorine to 18. Pool wouldn’t clear.

After 2 weeks we replaced 1/2 of water, [water was clear with the replacement] brought salt up to 3000 and CYA up to 60 again, pH 7.4, and SLAMMED again. Filter has been running for another 3 weeks and the water is very cloudy, but pool blue. Can’t see bottom.

Questions:

1. Could the chemicals or even the cover circles have destroyed the filter?
2. Replace sand or entire sand filter?
3. What about going to DE if sand is shot?
4. Any other thoughts would be much appreciated.

 

[1poolman1]

Hi everyone. I’ve never posted before. I have a 10,400 g fiberglass pool, pentair pump, 24” Hayward Pro sand filter [7 years old], Pentair heater, Hayward PS8 controller for SWG with T-15 turbo cell. For past 7 years have had crystal clear water within weeks of opening using TFP SLAM method and values during pool season. However, will also throw in that in the past 7 years have gone through 3 solar covers and the little blue dots I’m sure got into the sand filter. Not sure if they backwash out, but kinda assumed they did...

After pool was closed down last season, we took off cover while bricks were being re-sealed. The brick guys used polymeric sand and a top sealer applied with a sprayer, getting into the pool. I removed as much of the chemical sealer that polymerized on top the water as I could, then put cover back on and let winter go by. Enter 2024

I opened early [4/1/24] and the water was deep forest green but no chemical residue on top. Before turning on the equipment, mega-shocked for weeks with brushing until the bottom was visible [no equipment running], vacuumed the bottom to waste, then turned on filter. Despite SLAM’ing to CC <0.5 with CYA 60, salt 3000, pH 7.5 and taking Chlorine to 18. Pool wouldn’t clear.

After 2 weeks we replaced 1/2 of water, [water was clear with the replacement] brought salt up to 3000 and CYA up to 60 again, pH 7.4, and SLAMMED again. Filter has been running for another 3 weeks and the water is very cloudy, but pool blue. Can’t see bottom.

Questions:

1. Could the chemicals or even the cover circles have destroyed the filter?
2. Replace sand or entire sand filter?
3. What about going to DE if sand is shot?
4. Any other thoughts would be much appreciated.

Three things to look at. First, after 7 years it is possible that you need to add 50# of sand to the filter. Easy to do if that is a side-mount MPV.

Second, adding a couple of handfuls of cellulose fiber or DE the the skimmer with the pump running will coat the top of the sand bed and help get the very fine particles from the water. It will have to be added each time the filter is backwashed, which my be more often as the tiny stuff is trapped, until the water is clear.

Third, sand does not wear out, doesn't get "shot," but does get clogged, especially if polymeric sand got into the filter in large quantity. A "deep clean" (described elsewhere on this forum), not usually needed, but can help with that.

 

[Newdude]

If the sand is still sand like, even if its filthy, it will clean as good as new. If it's gummed up and/or rubbery then it's time for replacement. Many times it's just low as said above.

Deep Cleaning a Sand Filter

This post will walk you through the anatomy of a sand filter, and then provide a video at the end for how to deep clean your sand filter. The filter used in the photos and videos is a Hayward S180T top mount sand filter. The images are of a similar filter. Obviously not all filters are...

www.troublefreepool.com

 

[prarielakes2012]

Three things to look at. First, after 7 years it is possible that you need to add 50# of sand to the filter. Easy to do if that is a side-mount MPV.

Second, adding a couple of handfuls of cellulose fiber or DE the the skimmer with the pump running will coat the top of the sand bed and help get the very fine particles from the water. It will have to be added each time the filter is backwashed, which my be more often as the tiny stuff is trapped, until the water is clear.

Third, sand does not wear out, doesn't get "shot," but does get clogged, especially if polymeric sand got into the filter in large quantity. A "deep clean" (described elsewhere on this forum), not usually needed, but can help with that.

Thank you 1poolman1. Will go through these steps and report back

 

[prarielakes2012]

If the sand is still sand like, even if its filthy, it will clean as good as new. If it's gummed up and/or rubbery then it's time for replacement. Many times it's just low as said above.

Deep Cleaning a Sand Filter

This post will walk you through the anatomy of a sand filter, and then provide a video at the end for how to deep clean your sand filter. The filter used in the photos and videos is a Hayward S180T top mount sand filter. The images are of a similar filter. Obviously not all filters are...

www.troublefreepool.com

Great. Thank you Newdude. Really hoping not to have to replace the sand. Will let you guys know

 

[Bperry]

Hi everyone. I’ve never posted before. I have a 10,400 g fiberglass pool, pentair pump, 24” Hayward Pro sand filter [7 years old], Pentair heater, Hayward PS8 controller for SWG with T-15 turbo cell. For past 7 years have had crystal clear water within weeks of opening using TFP SLAM method and values during pool season. However, will also throw in that in the past 7 years have gone through 3 solar covers and the little blue dots I’m sure got into the sand filter. Not sure if they backwash out, but kinda assumed they did...

After pool was closed down last season, we took off cover while bricks were being re-sealed. The brick guys used polymeric sand and a top sealer applied with a sprayer, getting into the pool. I removed as much of the chemical sealer that polymerized on top the water as I could, then put cover back on and let winter go by. Enter 2024

I opened early [4/1/24] and the water was deep forest green but no chemical residue on top. Before turning on the equipment, mega-shocked for weeks with brushing until the bottom was visible [no equipment running], vacuumed the bottom to waste, then turned on filter. Despite SLAM’ing to CC <0.5 with CYA 60, salt 3000, pH 7.5 and taking Chlorine to 18. Pool wouldn’t clear.

After 2 weeks we replaced 1/2 of water, [water was clear with the replacement] brought salt up to 3000 and CYA up to 60 again, pH 7.4, and SLAMMED again. Filter has been running for another 3 weeks and the water is very cloudy, but pool blue. Can’t see bottom.

Questions:

1. Could the chemicals or even the cover circles have destroyed the filter?
2. Replace sand or entire sand filter?
3. What about going to DE if sand is shot?
4. Any other thoughts would be much appreciated.

Just to clarify, the SLAM you are describing is not TFP SLAM. Hard to say what mega-shock is, but the FC level for CYA level of 60 is 24ppm. Did you maintain 24ppm for several weeks?

Heres the detailed instructions:

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.

www.troublefreepool.com

 

[prarielakes2012]

Just to clarify, the SLAM you are describing is not TFP SLAM. Hard to say what mega-shock is, but the FC level for CYA level of 60 is 24ppm. Did you maintain 24ppm for several weeks?

Heres the detailed instructions:

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.

www.troublefreepool.com

Hi. The CYA was 0-20 when I first started the process. I did not start the TFP SLAM until after the filter was activated. And yes, I did maintain it at 20-27 for several weeks at that point in this saga. I don’t put salt and CYA in the pool and start the process until the bottom is clean enough to go a few says without vac. Been using TFP SLAM technique for over a decade, but certainly if some slight technical changes have been made since you joined, I would not be aware. What was in vogue when I was learning it has worked for me. I am using the term “mega slam” to reflect super high chlorine levels that occur with no CYA when starting clean up without immediate filter activation. Just a figure of speech. This was not a normal start-up year.