Where to start?

[Paul Indoor SWP]

10,000 gal, indoor salt water pool with Pentair system installed Feb 2021. Have struggled with high TA and pH and chlorine instability since. Purchased TF100 test kit and today's testing results were:
Free Chlorine-9 CC-1 TC-10
pH-8.2
CH-2375!
TA-220
CYA -110
Salt per Pentair reading-3900.
How to proceed? Thanks so much!

 

[HermanTX]

Just curious as to why do you have CYA in an indoor pool? Did you add this or were you using chlorine tablets that added the CYA? You state you have a Saltwater pool so not sure how the CYA got there.

Also, it may be best to retest your CH again. You need to use the 10ml sample and after adding 10 drops of R-0010 and 3 drops of R-0011L the solution should be Red to indicate calcium. Then add R-0012 one drop at a time until the solution turns a light blue. That is the end point. Number of drops x 25 is your CH level. Just want to verify that the test was done correctly.

Do you have high CH and TA in your fill water? Have you tested your fill water?

You can add muriatic acid to get pH to 7.8 level.

 

[Texas Splash]

Welcome to TFP! Yes, definitely run another set of test results to confirm those numbers. If the CH and CYA are indeed high, then a water exchange is no doubt the next step. For most indoor pools we recommend a CYA around 20 - 30 ppm.

Pool Care Basics Archives

Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!

www.troublefreepool.com

 

[Paul Indoor SWP]

We are not adding CYA but did use some chlorine tablets a couple months ago when working to get chlorine reading up. Retested and think it is closer to 50. That test is a tough one to read.

We will test our fill water. Two repeat tests of Calcium in pool water were 1625 and 1575. We have added 1/2 gallon Magic Acid a day for the last 2 days and total alkalinity is now 170, pH still 8.2. Added another 1/2 gal today after that reading. Thanks so.

 

[HermanTX]

We are not adding CYA but did use some chlorine tablets a couple months ago when working to get chlorine reading up. Retested and think it is closer to 50. That test is a tough one to read.

Ok that makes sense. In the future, when you cannot run your SWCG for whatever reason, best to use liquid chlorine.
Everyone has had some trouble with the CYA test until you do it a couple of times.

I find it best to add the solution to a known level such as 90 in your case and you should easily see the black dot. Then without looking down the tube, fill it to the 80 mark, then glance in the tube, if you see the black dot, then move to the next mark, i.e, 70 and glance again. Continue this until you cannot see the black dot. The reading before that one is your CYA level. So if you can see it at 50 but not at 40 then 50 is your CYA. This way, you are not staring at the black dot in the tube and by turning your eyes away from it then glancing back in when you have solution to the next mark, you tend to make a better determination if you see it or not. Hope this helps.

Also, you can remove CYA quickly by draining and refilling. You may get some slow diluting over time if you elect not to drain.

Have you tested your fill water? Is that what is driving your high CH and TA levels?

Here is a picture as well for CYA testing.

 

[Paul Indoor SWP]

Thanks so much for your wisdom. We are doing a partial drain and refill now and will also test our fill water. Thanks again!

 

[Paul Indoor SWP]

Did partial refill. Continuing 1/2 gal Magic Acid daily. Tested fill water.
Fill water: pH 7.8, Calcium 350 Total Alkalinity 240
Pool water: chlorine 15, chloramine 0.5, pH 8.0, Calcium 1350, TA 180, salt 2900, CYA 90. Should we empty more water?

 

[HermanTX]

Did partial refill. Continuing 1/2 gal Magic Acid daily. Tested fill water.
Fill water: pH 7.8, Calcium 350 Total Alkalinity 240
Pool water: chlorine 15, chloramine 0.5, pH 8.0, Calcium 1350, TA 180, salt 2900, CYA 90. Should we empty more water?

Since you have an indoor pool, you really do not need a lot of CYA. The CYA protects your chlorine from burn off due to UV.
So with your high CH and CYA, I would drain 75% mainly to get the CH down the most because your fill water has 350ppm CH but zero CYA.

 

[Paul Indoor SWP]

Have drained about 75%, pH 8.0, chlorine 4, chlorine 0.5, calcium 625 (purple) to 750 (red), alkalinity 200, salt 1650, cya 80-90.
Added 1/2 gal muriatic acid, 28# Mineral Springs Beginnings (sodium chloride, boron salt, sodium bisulfate and cyanuric acid - darn it!). Didn't look at content list until after husband added. This is the "salt" pool company delivered previously.

 

[HermanTX]

Have drained about 75%, pH 8.0, chlorine 4, chlorine 0.5, calcium 625 (purple) to 750 (red), alkalinity 200, salt 1650, cya 80-90.
Added 1/2 gal muriatic acid, 28# Mineral Springs Beginnings (sodium chloride, boron salt, sodium bisulfate and cyanuric acid - darn it!). Didn't look at content list until after husband added. This is the "salt" pool company delivered previously.

Great in lowering the calcium to a more manageable level.

Very unfortunate that any benefit of the new water to lower the CYA was offset by the salt addition.
I don't know how much CYA that 28 pounds of salt added but, you may want to test that CYA again as I noticed in earlier post that you, like many of us, find that CYA test challenging, so always good to do a second test.

Since you have an indoor pool, I think it is important to lower that CYA so you can reduce your level of FC needed to properly sanitize the water per FC/CYA Levels. However, it may not be a huge issue since you have a SWCG and that will manage your daily FC loss mainly due to bather load. Others may have more opinions on this.

You may need to consider another partial drain. Your fill water has CH of 350 and TA of 240 so be aware that those values if you do decide to do another partial drain.

 

[Paul Indoor SWP]

Our salt level only went up to 1900 with the one bag. What is your recommendation for what kind of salt to add that doesn't have CYA as we need to get salt up to 3600? Concerned chlorine has dropped to 4. Will SWG make chlorine at this salt level? Should we add liquid chlorine until salt level up? How much?

 

[Texas Splash]

When the salt level is below the recommended minimum for your SWG, it may stop producing chlorine. At that point you need to add liquid chlorine (or regular bleach) to keep the FC elevated until you resolve the salt issue. You can use a variety of salt products. Salt does not have stabilizer in it so it will not impact your CYA. Neither does liquid chlorine or regular bleach. Morton's water softener salt is one example. Hardware store solar salt bags are good to use and very pure.

 

[Paul Indoor SWP]

Thanks so much! Is there a spot on TFP that suggests how much salt and chlorine to add at what interval based on current readings?

 

[mknauss]

Thanks so much! Is there a spot on TFP that suggests how much salt and chlorine to add at what interval based on current readings?

PoolMath

 

[HermanTX]

I would highly recommend that you invest the $9 in the PM app noted by others. It is a good way to track your data.
On the pulldown menu there is an "effects of adding" where you can put in the size of your pool and the chemical volume to calculated what it will do. I put in 10000 gal pool, with 10% liquid chlorine - 1 gal of it will raise your FC 10ppm and it will raise salt by 16ppm (LC has salt in it as one of its other components). For regular salt - 10lbs will raise salt by 119ppm for 10000gals.

Once your salt is at proper level your SWCG should function. Raise your FC to your desired level with LC and then have the SWCG maintain it. So you will have to adjust the SWCG % based on how long it will run each day.
The PoolMath app has a function for SWCG as well to help you calculate % and time based on your specific unit.
Good Luck.