Best way to reduce FC?

[Pble]

History
2021 pool school in the spring, pool turned over to us, chemicals good all season

2022 FC consistently low (0.5, 0.1, 0.8, etc)
Total chlorine was below 1.0 during this time as well but also fluctuated.
Phosphates started to increase
Pool store says add 36 gallons of chlorine to break chlorine lock and lower phosphates.

Phosphates increase more and FC and TC sit at 15

Present day
FC and TC at 15
Phosphates increasing (even higher than last season)
7/3 FC & TC at 15, PH 7.4, phosphate 2067
7/6 FC & TC at 15, PH 7.2, phosphate 2170

Total alkalinity, calcium hardness; optimizer all low. CYA at 150.

Pool store says make sure pool is uncovered to burn off chlorine. Also, don’t worry about the other numbers because when the chlorine is high they won’t measure correctly.

I ask what to do to lower the chlorine they say add Chem-Out. I leave, didn’t buy anything. Irritated I was told last year to dump all the liquid chlorine in and now it’s too high.

This all brings me here as we recently discovered the site. The pool is crystal clear. It looks beautiful. No irritation on skin or eyes. Outside temperature has been keeping it around 80 degrees with the heater off. The filter run at 80% 7am-9pm and then 50% overnight. We have an automatic chlorinator and a new frogger pack was installed when pool store opened the pool this season. We have a Hayward heater, a Hayward Swimclear multi element cartridge filter and a Hayward TriStar Pump.

Please help. We are so tired of spinning our wheels and spending our money. If more info is needed please let me know and I’ll edit to add. Thank you sooo much TFP!!

 

[mknauss]

Welcome to the forum!

How to Chlorinate Your Pool

Before chlorinating your pool, you should know these simple tips. Learn the best way to add chlorine to your pool.

www.troublefreepool.com

I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - Trouble Free Pool

 

[Newdude]

Hey Pble and welcome !!!

Get off the pool store turnip truck. I had to fall off, but you have the option to do it gracefully and of your own accord.

All you need is a reliable test kit. We will teach you how to use it, and what to do every step of the way.

Test Kits Compared

The TFpro (Tfpro salt if applicable) from tftestkits.net are the hands down best value because they include a $48 stirring device that is a must have. Or add it to any of the other kits.

If you go with a k2006, make sure to get the k2006C. The non C is too small and you'll be replacing it too soon, but the price sure looks nice when your searching.

 

[duraleigh]

To answer the question in your title, do NOTHING the chlorine will come down on it's own very soon. Take the pucks out of the chlorinator until your chlorine is where you want it.

Read the articles mknauss has linked you to. Disregard phosphates completely for now.

 

[Bperry]

History
2021 pool school in the spring, pool turned over to us, chemicals good all season

2022 FC consistently low (0.5, 0.1, 0.8, etc)
Total chlorine was below 1.0 during this time as well but also fluctuated.
Phosphates started to increase
Pool store says add 36 gallons of chlorine to break chlorine lock and lower phosphates.

Phosphates increase more and FC and TC sit at 15

Present day
FC and TC at 15
Phosphates increasing (even higher than last season)
7/3 FC & TC at 15, PH 7.4, phosphate 2067
7/6 FC & TC at 15, PH 7.2, phosphate 2170

Total alkalinity, calcium hardness; optimizer all low. CYA at 150.

Pool store says make sure pool is uncovered to burn off chlorine. Also, don’t worry about the other numbers because when the chlorine is high they won’t measure correctly.

I ask what to do to lower the chlorine they say add Chem-Out. I leave, didn’t buy anything. Irritated I was told last year to dump all the liquid chlorine in and now it’s too high.

This all brings me here as we recently discovered the site. The pool is crystal clear. It looks beautiful. No irritation on skin or eyes. Outside temperature has been keeping it around 80 degrees with the heater off. The filter run at 80% 7am-9pm and then 50% overnight. We have an automatic chlorinator and a new frogger pack was installed when pool store opened the pool this season. We have a Hayward heater, a Hayward Swimclear multi element cartridge filter and a Hayward TriStar Pump.

Please help. We are so tired of spinning our wheels and spending our money. If more info is needed please let me know and I’ll edit to add. Thank you sooo much TFP!!

We’ll need two test numbers…free chlorine and the CYA (stabilizer) levels. The correct level of chlorine is dependent on how much stabilizer is in the water. If your CYA level is over 40ppm, you can safely swim at chlorine level of 16ppm.

The advice is prefaced on the accuracy of the pool store water test which if you hang around here very long will notice that pool store tests aren’t very accurate and their advice can be pretty terrible.

The related advice would be to get your own test kit (one of the two recommended on this site) and don’t step foot in the pool store again. TFP can help you out, but it’ll require you trusting your own test kit results and not the pool store.

 

[mgtfp]

If that CYA value of 150 is correct (which I doubt, it may well be even higher), then you don't want your FC to come down. FC 15 would only be a concern without CYA in the water, which I doubt is the case. But we don't actually know until you can test the water yourself.

The higher the CYA, the higher the FC needs to be to compensate for the chlorine that is attached to CYA, where it is protected from UV light, but doesn't have any sanitising effect anymore, and unfortunately still shows as "free" chlorine in the test. Chlorine attached to CYA is also not "aggressive" to bathers or equipment, any FC up to SLAM-level (but above minimum level) for the respective CYA is safe to swim in. See FC/CYA Levels.

Get started with getting a test kit as recommended above and reading through the recommended articles.

Welcome to TFP!

 

[Pble]

Thank you, all! We’ve ordered a testing kit and we look forward to getting more accurate results! We appreciate your insight and will update when we have new results to share. Thanks, again!

 

[Pble]

We received our kit. Here are the results from just a little bit ago. Chlorinator has been off and pucks removed since (7/6) it was recommended above. The pool has been closed the last 3 days while traveling but otherwise has remained open. We will continue to leave it open being home now. Is there anything we should do?

 

[ajw22]

Was the CYA 125 determined through a 1:1 dilution test?

For CYA > 90ppm, repeat the test adjusting the procedure as follows:

1. Fill the mixing bottle to the lower mark (15 ml line) with pool water.
2. Continue filling the mixing bottle to the upper mark (30 ml line) with tap water.
3. Shake briefly to mix.
4. Pour off half of the contents of the mixing bottle, so it is again filled to the lower mark (15 ml line).
5. Continue the test normally from adding R-0013, but multiply the final result by two.

If you need to dilute the pool water further then apply these ratios:

Pool water	Tap or distilled water	Multiply result by
1	1	2
1	2	3
1	4	5

Note that when doing a diluted test not only do you multiply the range of the test you multiply the error rate of the test, so results are a ballpark - not an absolute.

See CYA Testing for tips in how to read the test results.

 

[Pble]

Ok, we did as mentioned and now got CYA 170.

 

[Newdude]

Ok, we did as mentioned and now got CYA 170

You'll need to exchange 75% to 80% of the water.

See this link to hatch a plan from a couple choices. Draining - Further Reading

 

[Pble]

While we are wrapping our heads around needing/figuring out the best way to exchange 75-80% of the pool water as suggested above, we have tested again. These are todays results. Everything has come down except CYA which appears to have increased (the CYA result is based on the dilution test recommended above). Are there any new suggestions based on todays results? The pool has remained uncovered and open all week and chlorinator is still off with no tabs. Thanks so much for your advice.

 

[JJ_Tex]

If you are comfortable in your CYA number of 200 using the dilution method, you now need to exchange 90% of your water.

Before you do that, why is your CYA increasing so much? You said no pucks for the last few weeks, but how are you chlorinating your pool?

 

[Bperry]

View attachment 516146
While we are wrapping our heads around needing/figuring out the best way to exchange 75-80% of the pool water as suggested above, we have tested again. These are todays results. Everything has come down except CYA which appears to have increased (the CYA result is based on the dilution test recommended above). Are there any new suggestions based on todays results? The pool has remained uncovered and open all week and chlorinator is still off with no tabs. Thanks so much for your advice.

Going swimming and getting some good splash out would get a tiny bit of CYA out. Enjoy the water until you have time to replace water.

 

[mgtfp]

I guess that CYA increase can be put down to testing inaccuracies. The CYA test at these levels is fishing in murky water. Just getting the dilution ratio slightly wrong will change the test results. And the dilution itself already doubles the testing error.

 

[Pble]

Thank you all so much. Appreciate all your responses. I tested all chemicals today and we either have some movement in the right direction regarding CYA or perhaps there was testing error (husband vs me as tester, full sun with sun at back vs indoor, etc). CYA is still high but way better than possible 200 prior. Is the FC and CYA more in line with each other now? I realize they are both high but it’s my understanding after a lot of reading it is ok if they are high together. Todays additional question would be should we be concerned that the CH has increased? Again, perhaps that difference is due to testing variables, etc.? Thank you!!

 

[JJ_Tex]

You are correct that the CYA number drives your FC number. If you have higher CYA you will need more FC than someone with a lower CYA.

At 95, you would round up to 100. Your FC is right in line with the recommended levels for your CYA. Don’t let it drop much lower or you will get algae. See my signature for the link to the chart including the specific ranges for your CYA.

Also I would recommend verifying the CYA using the dilution method. I don’t want you thinking you have a good level of chlorine, and then later find out your CYA was really higher and you end up with algae.

 

[Pble]

You are correct that the CYA number drives your FC number. If you have higher CYA you will need more FC than someone with a lower CYA.

At 95, you would round up to 100. Your FC is right in line with the recommended levels for your CYA. Don’t let it drop much lower or you will get algae. See my signature for the link to the chart including the specific ranges for your CYA.

Also I would recommend verifying the CYA using the dilution method. I don’t want you thinking you have a good level of chlorine, and then later find out your CYA was really higher and you end up with algae.

We have been using the dilution 1:1 method that ajw22 recommended in an earlier response. Today I did it 3 times reusing the solution I made. Each time it came out at 95. Before doing it this way I did the method listed on the card that came with the testing kit and the number was much higher (below the 100 line by almost 1/2).

 

[ajw22]

We have been using the dilution 1:1 method that ajw22 recommended in an earlier response. Today I did it 3 times reusing the solution I made. Each time it came out at 95. Before doing it this way I did the method listed on the card that came with the testing kit and the number was much higher (below the 100 line by almost 1/2).

Don't sweat the CYA test.

Call your CYA 100 and move on.

The CYA test is not that precise to worry about +/- 10 ppm.

 

[mgtfp]

We have been using the dilution 1:1 method that ajw22 recommended in an earlier response. Today I did it 3 times reusing the solution I made. Each time it came out at 95. Before doing it this way I did the method listed on the card that came with the testing kit and the number was much higher (below the 100 line by almost 1/2).

Just to clarify: When you do the 1:1 dilution method, you have to double the reading.

The purpose of the dilution is to half the amount of CYA in the sample you are going to test so that the reading will be within the available scale. But then you have double the reading to "undo" the dilution.

It sounds to me that your CYA still is somewhere around 200.