New to TFP. Struggling to maintain chlorine levels

alison.s27

New member
Dec 24, 2024
4
Perth, Western Australia
Pool Size
60000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Astral VX 7T
Hi. I’m in sunny Western Australia and after a few months of getting no where with our forever cloudy pool and low chlorine levels (dropping to 0.5FC) despite SWG running at 100% and pool shop not really interested in getting to the bottom of why, I stumbled across TFP.

We have a beautiful tree that drops flowers constantly over summer. We have a pool blanket that is on when we aren’t in the pool - although pool shop says we should do 2 days on and 1 day off… haven’t found what TFP think about this!

Last year we struggled with a cloudy pool all summer. We replaced the SWG, bought a new robot vacuum (Dolphin Liberty 400). The pool shop technician came out and tipped a phosphate treatment in the pool and it went cloudy which he said meant we had high phosphates and needed to use phosphate remover. Then this summer, despite doing that, it still hasn’t looked “crystal clear”. Pool shop has had us adding 250g of Diclor each time to get it up to “target” (3-4ppm) but when we’d go back 3-4 days later, FC was back to really low again.

The Taylor’s kits are hard to get in Oz so I’ve purchased a Clear Choice Labs kit which I understand is an Australian made equivalent.

On testing our own pool water at the beginning we were at with SWG running at 100% for 10hrs a day.
FC 0.5
CC 0.5
PH 7.4
TA 125
CH 225
CYA 30
Salt 6400
Temp 26 degrees Celsius.

Bar the chlorine levels, our pool shop said these were all in range but I understand from TFP that this view isn’t shared here.

So I’m following the SLAM and already the pool looks MUCH clearer.

My questions:
1) We are using 12.5% liquid chlorine and have used 13L in 2 days. If we test then add chlorine at sundown, should we retest some time period later (?30 minutes ?2hrs) to know what our FC is so we can do the OCLT?

I know pool maths says it should be 12 based on what we’ve added but I’m suspicious whether the liquid chlorine is “fresh” and understand that more concentrated liquid chlorine deteriorates more rapidly on the shelf.

2) when we exit the SLAM and restart our SWG, do we just follow the Pool Math recommendation for what percentage to run it at and number of hours to run filter? Then test daily to make sure it’s “right”?

3) I understand lots (most) of our other numbers are low. Do we correct one thing at a time? Is there a specific order we should follow?

4) we will also need to top the pool water up a bit from the tap. I assume we do this first, then redo all the chemistry, then correct?

Thanks! (Hoping my signature is set properly too!!)
 

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Welcome to TFP!

I took a glance at your SWCG manual, because I know Australian units operate a little differently. It says 30-60ppm CYA and 4000ppm salt. From the manual “Keep the Stabiliser reading between 30 and 60ppm”

Low CYA seems the most likely problem. Sunlight rapidly consumes the chlorine being produced. Most people in the US run CYA around 70ppm as is recommended by the manufacturers.

High salt could be an issue as well. My SWCG manual warns that high salt can result in damage to the cell. I don’t know about yours, but it’s not out of the question a cell could shut down if the salt level is too high. From the manual “Salt level should be maintained around 4,000ppm but should never be allowed to fall below 3,000ppm.”

I believe if you raise your CYA, you’ll find the pool holds chlorine better.

A good way to test the output of the chlorine generator is to collect a water sample directly from the return. This should test notably higher than the pool water while the generator is running.
 
1) We are using 12.5% liquid chlorine and have used 13L in 2 days. If we test then add chlorine at sundown, should we retest some time period later (?30 minutes ?2hrs) to know what our FC is so we can do the OCLT?

I know pool maths says it should be 12 based on what we’ve added but I’m suspicious whether the liquid chlorine is “fresh” and understand that more concentrated liquid chlorine deteriorates more rapidly on the shelf.

Until you are familiar with your chlorine source and your pool, you should test 20 minutes after adding Liquid Chlorine to confirm that the FC is up to your SLAM level of 12.

You do not need to wait until sundown to add the chlorine. Test anytime during the day and add the chlorine whenever the level is below your target.

2) when we exit the SLAM and restart our SWG, do we just follow the Pool Math recommendation for what percentage to run it at and number of hours to run filter?

Where are you getting Pool Math recommendation for what percentage to run it?

Then test daily to make sure it’s “right”?

You dial in your SWG % with minor adjustments up and down as the seasons change.

Once your FC is around your target, if it is rising, dial the SWG down a bit, and if it is decreasing, dial it up a bit.

As you get the SWG % dialed in, you can take more time between tests and adjustments.
3) I understand lots (most) of our other numbers are low. Do we correct one thing at a time? Is there a specific order we should follow?

FC 0.5 - LOW
CC 0.5 - OK
PH 7.4 - Anywhere in the 7's is OK
TA 125 - OK
CH 225 - OK
CYA 30 - LOW
Salt 6400 - HIGH

Once the SLAM process is completed, then get your FC and CYA up to recommended levels.

Keep your pH in the 7's.

Reduce your salt by draining the pool 30%.

You can work on all of that at the same time.

4) we will also need to top the pool water up a bit from the tap. I assume we do this first, then redo all the chemistry, then correct?
Topping off the pool will not significantly change the chemistry.

Get more active in moving the pool to the desired levels.
 
t
Welcome to TFP!

I took a glance at your SWCG manual, because I know Australian units operate a little differently. It says 30-60ppm CYA and 4000ppm salt. From the manual “Keep the Stabiliser reading between 30 and 60ppm”

Low CYA seems the most likely problem. Sunlight rapidly consumes the chlorine being produced. Most people in the US run CYA around 70ppm as is recommended by the manufacturers.

High salt could be an issue as well. My SWCG manual warns that high salt can result in damage to the cell. I don’t know about yours, but it’s not out of the question a cell could shut down if the salt level is too high. From the manual “Salt level should be maintained around 4,000ppm but should never be allowed to fall below 3,000ppm.”

I believe if you raise your CYA, you’ll find the pool holds chlorine better.

A good way to test the output of the chlorine generator is to collect a water sample directly from the return. This should test notably higher than the pool water while the generator is running.
Thanks!

Yes since taking a more active approach, I’d found the manual and noticed that recommendation re: salt. We bought the SWG from the pool shop yet they’ve been recommending we maintain salt levels between 5000-6500ppm. I found this so we’ll work on bringing it down to 4000 but looks like it will run OK up to 8000

IMG_8629.png

As for CYA, the pool shop said their “normal range” is 30-100. Agree that as per the SWG, we’ll now aim to bring the stabilizer up closer to 60 once we finish the SLAM.

We did the OCLT last night and it fell by 2ppm so not quite there yet.
 
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Until you are familiar with your chlorine source and your pool, you should test 20 minutes after adding Liquid Chlorine to confirm that the FC is up to your SLAM level of 12.
Perfect. Thanks. Will do that from now on.

You do not need to wait until sundown to add the chlorine. Test anytime during the day and add the chlorine whenever the level is below your target.
Yes we’ve been adding chlorine during the day but was waiting until sundown to do the last addition to help with OCLT.
Where are you getting Pool Math recommendation for what percentage to run it?
When I first input all our numbers into PoolMath, it would let me put my SWG model in and it gave a suggestion of percentage to run at based on current run time of filter.

You dial in your SWG % with minor adjustments up and down as the seasons change.

Once your FC is around your target, if it is rising, dial the SWG down a bit, and if it is decreasing, dial it up a bit.

As you get the SWG % dialed in, you can take more time between tests and adjustments.
Thanks. Will start this once SLAM done.
FC 0.5 - LOW
CC 0.5 - OK
PH 7.4 - Anywhere in the 7's is OK
TA 125 - OK
CH 225 - OK
CYA 30 - LOW
Salt 6400 - HIGH

OK.
So our pool shop had recommended the following

FC 2-4
CC 0-0.2
Salt 5000-6500
PH 7.2-7.6
TA (adj) 100-150
CYA 30-100
CH 125-350

But PoolMath
- adjusts FC based on CYA
- salt as per our SWG manual should be around 4000
- CYA 60-90 (although appreciate JohnTs post that things are a bit different in Oz so as per our SWG will aim for 60)
- CH 350-550 ideally
- ph 7.6-7.8 ideally.

Have certainly been impressed with how quickly the pool has cleared with the SLAM so feeling confident that TFP recommendations are the right way to go.

Thanks for your tips.

Once the SLAM process is completed, then get your FC and CYA up to recommended levels.

Keep your pH in the 7's.

Reduce your salt by draining the pool 30%.

You can work on all of that at the same time.


Topping off the pool will not significantly change the chemistry.

Get more active in moving the pool to the desired levels
 
So our pool shop had recommended the following

FC 2-4
CC 0-0.2
Salt 5000-6500
PH 7.2-7.6
TA (adj) 100-150
CYA 30-100
CH 125-350
Ignore these^^^

  1. Run you FC for your CYA. Never get close to minimums.
  2. Use the salt level recommended by the SWG manufacturer.
  3. Any pH in the 7s, even up to 8 is fine. No need to raise pH...it will rise on its own. When your TA is >80, when pH gets to 8, lower your pH to 7.4-7.6 with muriatic acid. When TA gets to 80, STOP lowering to 7.4-7.6 and only lower to 7.8. With a TA of 60-80, your pH should be fairly stable around 7.8-8.
  4. TA should be 60-90. Pool store recommendation is for people that use tabs to chlorinate. Tabs are acidic and high TA offsets the acidity.
  5. No need to "adjust" TA.
  6. While you are learning your pool, I would not run CYA above 60. Too hard to SLAM. When you learn your pool, and are avoiding the need to SLAM, then raise to 70/80. I would not go above.
  7. CH is not necessary in a fiberglass pool, unless you have a tile waterline, or a gas heater. If you ever experience foaming, you might find 120-150 will get rid of the foam.

 
Ignore these^^^

  1. Run you FC for your CYA. Never get close to minimums.
  2. Use the salt level recommended by the SWG manufacturer.
  3. Any pH in the 7s, even up to 8 is fine. No need to raise pH...it will rise on its own. When your TA is >80, when pH gets to 8, lower your pH to 7.4-7.6 with muriatic acid. When TA gets to 80, STOP lowering to 7.4-7.6 and only lower to 7.8. With a TA of 60-80, your pH should be fairly stable around 7.8-8.
  4. TA should be 60-90. Pool store recommendation is for people that use tabs to chlorinate. Tabs are acidic and high TA offsets the acidity.
  5. No need to "adjust" TA.
  6. While you are learning your pool, I would not run CYA above 60. Too hard to SLAM. When you learn your pool, and are avoiding the need to SLAM, then raise to 70/80. I would not go above.
  7. CH is not necessary in a fiberglass pool, unless you have a tile waterline, or a gas heater. If you ever experience foaming, you might find 120-150 will get rid of the foam.

Thank you!!
 
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One other thought.
You don't need to do anything to get your TA down from 125 to 60-80, other than using muriatic acid to lower pH when pH gets to 8.
Acid will lower both pH and TA.
pH will rise, on its own, naturally.
By managing pH, your TA will come down over time.
 
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