Calcium Precipitate

[milosmanzer]

Any observations suggestions would be greatly appreciated.

My problem is calcium precipitate (snow flakes) have been showing up in the last week. I placed a pinch of the stuff from my robot into a bit of muriatic acid and there was a good reaction. I'm fairly positive it is calcium. The amount that my robot picked up (3hr cycle) is equivalent to the size of a pocket watch of white calcium flakes in the basket. Trying to avoid scaling, see history below. My readings as of this morning are PH: 7.2 TA: 140 CH: 425 water temp: 70-75f. Base fill water measurements for Vegas are 7.6, 165 and 260, respectively. I opened my pool about 3 weeks ago with no sign of precipitate in my filter or loose in the pool. Opening the pool included about a 10k gal fresh water swap (20k gal pool), mostly daily muriatic acid added to keep PH down near 7, SWG cleaning and startup (was using liquid chlorine through the winter once the temp dropped), pool salt added up to about 3500 ppm, CYA added up to 59 ppm so far (trying to get it to 75ppm today). Other readings are FC: 3.5 CYA: 59 CSI -0.26.

My plan is to continue daily muriatic acid to keep PH near 6.8-7.2. I'll chase it until I get TA into the 50-90 range. My TA has dropped from 150 in the last 3-4 days or so. I don't plan to water swap due to the time it takes (usually 5-6 days to add 10k gal with a pump removing about the same). The diminishing returns on reducing CH make the process a chore, as I'm pumping out some of the fresh water I just added. Anyway, when I break down the pool in the fall/winter I'll probably water swap again at that time.

History: The pool was built Jan-Apr 2023 and started swimming in June or so. No issues until the following Spring, 2024. Last spring I noticed a huge amount of precipitate (pop up heads were pushing small piles of snow) Mar 2024 as the water started to warm up. This was before my mad scramble to learn everything on TFP. When I discovered a huge scaling problem around May 2024, to the extent that it was cutting arms, legs and feet, I got invested with TFP and fired my pool care company. I think the plaster bled quite a bit of calcium into the water. I know he managed the chlorine with lots of tabs to supplement my SWG. I think this combination was a recipe for disaster. At the time I started monitoring my chemistry, my CH was in the high 600s, Ph was as high as it could go, TA was near 200 and the pool temps were in the 75-80f range. I drained and filled to get the levels manageable, re-salted, Ph down, etc.

 

[mknauss]

Welcome to the forum!
What test kit are you using?
The high TA is causing calcium scale to occur in your SWCG. You need to get the TA down in the double digits, with the CSI in the -0.3 to 0.0 range.
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

 

[PoolStored]

You are doing the right thing (lowering TA). Some find that they need to run CSI down around -.4 to eliminate scale. @mas985

 

[milosmanzer]

Welcome to the forum!
What test kit are you using?
The high TA is causing calcium scale to occur in your SWCG. You need to get the TA down in the double digits, with the CSI in the -0.3 to 0.0 range.
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

Thanks for the quick response- Taylor K-2005 Complete is the test kit. The high TA makes a lot of sense- as it started occurring as soon as I booted up the SWCG. I'll just keep returning to the muriatic acid well until the TA numbers drop to double digits. Thanks for the insight!

 

[milosmanzer]

You are doing the right thing (lowering TA). Some find that they need to run CSI down around -.4 to eliminate scale. @mas985

Thanks for the quick response. I'll keep on plan until I see the TA numbers drop. I don't have much scale this season, the plaster is smooth still. Not abrasive like last year. But I want to keep that from happening. I'll continue to monitor the CSI, hopefully I can get it down there via the TA drop. Not much I can do to the CH.

 

[mknauss]

Great. As our use of fill water increases, you will need to add acid 2 or 3 times per week to try and drop the TA.
I hope you are using softened water for make up water, keeps the CH levels in check.

Also consider getting a FAS-DPD kit so you can measure FC accurately.

 

[milosmanzer]

Great. As our use of fill water increases, you will need to add acid 2 or 3 times per week to try and drop the TA.
I hope you are using softened water for make up water, keeps the CH levels in check.

Also consider getting a FAS-DPD kit so you can measure FC accurately.

Will keep up the acid work. I use water from the tap as fill water. The CH of tap is around 165 here in Vegas, from my faucet anyway. Which is way lower than my 425. Is there a thread describing options for softening water? I'll look into the FAS-DPD kit. My reagents are only DPD. I'll try and find the one TFP sells. This one is about 1.5 yrs old. So, probably should get a new one. In addition, I can't detect lower than 7.0 PH on my test kit. Does the TFP kit indicator show sub 7.0?

 

[PoolStored]

The CH of tap is around 165 here in Vegas, from my faucet anyway. Which is way lower than my 425.

Evap and fill will still raise your CH, even with 165 fill. CH doesn't go away, it accumulates.
Softening water is getting a water softener and using the output of the softener to refill/autofill your pool. CH will be 0 or close and won't add CH.
If your reagents are 1.5yrs old, in Vegas, I'd get this kit and don't look back. Link-->TF-Pro Salt
Keep it in a cool, dry (vegas duh), dark location and they will last longer.
Yes, it will show you if pH is lower than 7 on the comparator. Will not tell you how much below...

 

[proavia]

Will keep up the acid work. I use water from the tap as fill water. The CH of tap is around 165 here in Vegas, from my faucet anyway. Which is way lower than my 425. Is there a thread describing options for softening water? I'll look into the FAS-DPD kit. My reagents are only DPD. I'll try and find the one TFP sells. This one is about 1.5 yrs old. So, probably should get a new one. In addition, I can't detect lower than 7.0 PH on my test kit. Does the TFP kit indicator show sub 7.0?

The TF-Pro Salt will serve you well.

pH needs to be kept in the 7's. Usually 7.2-7.9 range, based on your other test results.

You can install a whole house water softener and plumb it to your autofill line.
Or you can install a portable RV style softener near your autofill feed line. But the portable softener will need more frequent recharging and it's a manual operation.

 

[milosmanzer]

Evap and fill will still raise your CH, even with 165 fill. CH doesn't go away, it accumulates.
Softening water is getting a water softener and using the output of the softener to refill/autofill your pool. CH will be 0 or close and won't add CH.
If your reagents are 1.5yrs old, in Vegas, I'd get this kit and don't look back. Link-->TF-Pro Salt
Keep it in a cool, dry (vegas duh), dark location and they will last longer.
Yes, it will show you if pH is lower than 7 on the comparator. Will not tell you how much below...

Isn't much I can do about my CH except manage the TA and hope for the best. TF-Pro Salt will be my next kit for sure.

 

[milosmanzer]

The TF-Pro Salt will serve you well.

pH needs to be kept in the 7's. Usually 7.2-7.9 range, based on your other test results.

You can install a whole house water softener and plumb it to your autofill line.
Or you can install a portable RV style softener near your autofill feed line. But the portable softener will need more frequent recharging and it's a manual operation.

Will try to keep managing TA, for sure. Probably stuck with the drain and fill method to keep CH from creeping over 500. Those softeners sound pricey.

 

[proavia]

You can mange CH up to about 800 before you need to drain/refill. As the CH rises, you need to keep the pH a bit lower (but still in the 7's) to keep the CSI in the 0.00 to -0.30 (negative 0.30) range.

A whole house water softener will provide benefits in addition to keeping your pool CH in check.
Soft water to all faucets, toilets, dishwasher, washer will minimize calcium buildup in pipes/appliances, allow using less soap and help keep your skin from drying out as fast.

Look in your garage near the water heater to see if there is already a soft water loop plumbed in. Many builders have added them in the last 20 years in areas with hard water. If you have one, it makes hooking up the water softener that much easier. If you decide to go that route, we can discuss further. In the mean time, Google - benefits of a water softener