CH and Salt High

[wjmano]

I'm very new to managing my pool and ran my first set of TF-Pro tests today. Everything seemed reasonable, except for salt and CH, with a 49% water replacement suggested to correct CH! The plaster pool is only 5 months old. I would appreciate any advice on what I should do. Here are my test results:

FC - 1.5
CC - 0
pH - 7.8
TA - 90
CH - 875
CYA - 75
Salt - 4000 (SWG reports 3500)

I've already tweaked the pH and FC as suggested by the Pool Math app.

Thanks!
Bill

 

[YippeeSkippy]

Are you saying PoolMath app said to correct your CH? Well, it *is* kinda high... did it suggest another water exchange?

Are you sure you did the CH test correctly? You haven't been using CalHypo or calcium containing "shock" products have you? Please repeat that test after reviewing the directions again, okay??

I would not worry about the salt level. Knowing you;re in FL I know you're going to get rain that requires a bit of lowering the water level. THat will remove some salt. And my theory is "IF the SWG is happy and making FC, I don't care what the number is".

Maddie

 

[YippeeSkippy]

If your CH is truly 875ppm now, I would suggest until you can drain down some to bring it to ~500ppm that you keep your pH on the low end like 7.2, which will help you avoid scale buildup.

 

[wjmano]

Thanks Maddie. I think I did the CH test correctly. Yesterday I got 775, so I decided to re-run it today and got 875.

I did use a CalHypo shock product a couple weeks ago, before finding this TFP website. Guessing that's a no-no?

 

[YippeeSkippy]

Yeah, in the sense that you were probably looking to add chlorine but you got extra calcium with that chlorine, right?

Go for the Liquid Chlorine every time. Nothing else to sneak up on you chemistry wise.

Maddie

 

[Rancho Cost-a-Lotta]

Bill,

Are your sure you used a 10 mL sample and not a 25mL? That would explain a false high result. Are you using a Smart Stir?

When performing the CH test (or any drop-based test), hold the reagent bottle completely vertical, and allow the drops to fall off the tip. If you don't have a Smart Stir, make sure you swirl well between drops and watch closely for the color change.

Try testing the CH of your fill water and report back. An unrealistic high number may suggest testing error or bad reagents.

 

[wjmano]

Hi Mike. I'm quite sure I did the CH test with 10 mL of water. I also did it twice over two days and got similar readings...775 and 875.

I also tested my tap water which runs through a whole house filter and potassium-based water softener and got zero calcium, as the R-0011L reagent did not turn the sample red at all.

My pool was filled before the whole house filter and softener was installed and I'm not sure where my auto-fill taps into my home water system. I'll need to call my pool contractor to determine this.

Guess bad reagents could be a possibility, but the test kit is brand new. Maybe I'll take a water sample into the pool store to get their CH assessment before I do anything else.

Thanks for your help.

 

[YippeeSkippy]

If you just bought the test kit I'm sure that one is fresh with new reagents.

 

[Rancho Cost-a-Lotta]

Hi Mike. I'm quite sure I did the CH test with 10 mL of water. I also did it twice over two days and got similar readings...775 and 875.

If you're confident you did the test correctly, trust your result. Going to a pool store will only confuse things. Your CH level is 775. Read up on Calcium Saturation Index (CSI). To avoid scaling, maintain CSI in the range of 0.0 to -.30. CSI is most easily managed by adjusting pH and TA. Looking at your results now, you can achieve a negative CSI by maintaining pH at 7.4 (@ 80 degree water temp).

Your goal now is to keep CH levels from increasing. It's important to test your fill water. It's likely connected to an outdoor water source or irrigation system. CH does not evaporate so levels will continue to increase as CH-laden fill water is added to the pool. It would be of great benefit to hook up the autofill to your home water softener system. You can drain smaller amounts overtime and replace with as much softened water as your system will allow. You can also use rainwater to your advantage.

Five months is way too soon to see CH levels at 775. Maybe too much at start-up, maybe too much cal-hypo, or maybe super high CH levels in your fill water. Either way, you can fix it for good by using softened fill water.

 

[wjmano]

Thanks Mike. I'll likely go ahead and replace about 50% of my water.

I'll use the softened water, but I'm being told the softener won't be able to keep up. Once the softener's effectiveness drops, I'll just end up with some harder water.

I may also reconfigure my autofill to pull softened water but this will require some plumbing changes. So before doing this, want to test the non-softened water to confirm the change is warranted for what I assume is a minimal amount of autofill water. My home is plumbed in a way that makes this difficult, so may just test my neighbors water.

Thanks again for your help.

 

[Rancho Cost-a-Lotta]

Sounds like a good plan. If you find your fill water is high in calcium, you'll have to decide if it's worth the cost to plumb soft water to the autofill.

While your testing, might as well check the TA and pH of the fill water. It will give you a clue how fill water will affect your chemistry.