Filter cartridge help

panchordoquy

New member
May 6, 2019
3
BAKERSFIELD, California
Hey, all:

First time, long time. I just purchased new filter cartridges after my old ones wore out (approximately 6-7 years). I bought these on Amazon, and have not been able to get the algae out of the pool for about 4 weeks. I have tried running the pump overnight, shocked the pool multiple times, checked levels, etc. and I don't know what to do.

With my old filters, if I got the chlorine and PH levels right, I could run the pump overnight to clear up an algae bloom. The pool would be almost clear by the next morning. Did I buy lousy filters? Is there a problem somewhere else in the system that I should be checking?

Paul
 

HermanTX

Gold Supporter
May 20, 2020
1,926
Katy TX
Pool Size
14600
Surface
Plaster
Chlorine
Liquid Chlorine
You do not have your test data in your post so it would be good to post the FC, CC and CYA level as a minimum.
You say you shock but do you do a full SLAM to ensure the algae is truly gone?

Not sure what the relationship between algae and filter other than you hope for the circulation to pick up the dead algae and captured by filter. Do you think you may have a hole in one of your filter grids? Do you have a cartridge or a DE filter?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
26,252
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Welcome to TFP.

Filtering does not fix an algae problem, chlorine does, in the correct amounts for the necessary time.

I suggest you review our SLAM Process and read ABCs of Pool Water Chemistry. We can take you through it and you need your own good test kit - a TF-100 Test Kits or Taylor K-2006C.

We don’t “shock” a pool...



How do you chlorinate your pool?

What test kit do you use?
 

panchordoquy

New member
May 6, 2019
3
BAKERSFIELD, California
Understood - thanks, guys. To clarify, in the past with my old filters, I would elevate the chlorine levels to about 6 ppm which (I always assumed, anyway) killed the algae and then the filters trapped the dead algae leaving me with a clear pool. I never had to go through a full SLAM process on the pool to achieve this. The only difference I can see this time around is this was the first algae bloom with my new cartridge filters.

I've elevated the chlorine level with 6+ ppm multiple times (CYA between 30 and 40, pH is between 7.5 and 7.2 during this period). My levels as of this morning are:

FC: 8.0 ppm
CC: 0.25 ppm
pH: 7.5
CYA: 40 PPM
TA: 120 PPM
Fiberglass pool

I have gone through the SLAM process once before and can do so if you guys think it's necessary, I've just never had algae hang on for so long, so I'm a little perplexed. When I used the term "shock", it was because I put a couple of shock packets in out of desperation and because my CYA was a little low. We accidentally overfilled the pool a couple of weeks ago, and the CYA usually dips when that happens. Thanks again for reading and providing feedback!
 

Pool_Medic

In The Industry
Apr 1, 2018
1,522
Bangor Maine
You’ve lucked out in the past, TFP uses proven methods not pool store magic where they just say try this, this, this and that. It’s only been recently that this industry has acknowledged the relationship between CYA and Chlorine.
 

PoolGate

Gold Supporter
TFP Guide
Jun 7, 2017
6,133
Damascus, MD
Pool Size
29000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Jandy Aquapure 1400
Clear water is a function of properly balanced water, not your filter (to a certain extent). I suspect you may have reached a point where your chlorine is no longer effective most likely due to high cyanuric acid (CYA). You should do a full battery of tests with a proper test kit like recommended on this site. Post results here.

NOTE: A proper test kit does not include any form of test strips or pool-store testing.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
26,252
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
I have never had algae in my po0ol in over 20 years. You keep on fighting algae because you never really do a full SLAM Process.

SLAM FC is 16 with CYA 40. With your FC of 6+ you are just tickling the algae. See FC/CYA Chart

Do the SLAM Process correctly and get rid of the algae then follow the FC/CYA Chart and TFP methods.
 
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