Calcium Flakes in Properly Balanced Pool with SWG

Rancho Cost-a-Lotta

Silver Supporter
Apr 10, 2018
2,378
Rancho Cucamonga, CA
Pool Size
18735
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45
I'm seeing calcium flakes coming from the returns, most likely being generated in the SWG cell. I collected some flakes this morning with the net and they tested positive for calcium (MA drops test). The flakes are soft and dissolve on contact.

Test results:

FC: 8
CC: 0
pH: 7.6 (Ranges from 7.2 to 7.6)
TA: 80
CH: 525
CYA: 80
CSI: -0.06 (Ranges from -0.33 to -0.06)
Temp: 82-87 degrees

Fill water TA is 130. To battle rising TA, I aerate daily using the spa spillover and add MA every other day to knock pH back down to 7.3 ppm from the 7.6 to 7.7 range. CSI rarely, if ever, gets into the positive range.

Curious what in my chemistry is causing the calcium flakes.

I suppose I'm a good candidate for borates?
 
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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
43,626
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
I suppose I'm a good candidate for borates?
Yes. The elevated water temperatures are pushing you into the scaling. The borates will moderate the pH rise in side the SWCG cell that causes the scaling.
 

Rancho Cost-a-Lotta

Silver Supporter
Apr 10, 2018
2,378
Rancho Cucamonga, CA
Pool Size
18735
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45
Thanks Marty.

Would this be happening with a lower CH level but similar CSI ranges? I'm assuming my CH is the culprit?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
43,626
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Right now my CH is 300 with a TA of 100 and pH in the upper 7's, water temperature gets to 90 in the afternoon and no flakes. So a lower CH will help. TA can effect it to, but getting yours any lower with your fill water is a challenge.
 

Rancho Cost-a-Lotta

Silver Supporter
Apr 10, 2018
2,378
Rancho Cucamonga, CA
Pool Size
18735
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45
To follow up on this thread, I ended up adding 50 ppm of granular boric acid to the pool. I'm no longer seeing calcium flakes. There's a little more to the story though...

Since the original post, I began to aggressively lower my TA to the 60-70 ppm through aeration (spa and waterfall) and MA dosing. I knew that lowering TA with borates in the pool would challenging. I'm now running my pH on the lower end of the range while keeping CSI above -0.30.

Prior to adding borates, I was adding at least 16 oz. of 31.45% MA every couple days to bring down pH. In the last four days since adding borates, I haven't added any MA. My pH has only risen from 7.3 to about 7.6. I'm hoping it will stabilize in the 7.6 to 7.7 range with the lower TA, but with my higher TA fill water I'm not holding my breath. If nothing else, I have no more flakes and won't need to add MA as often.

Thanks for the help Marty!
Ho do you know how much to add? I don't see it in this thread.
Here's some reading material:

Make sure you have a good handle on your pool's chemistryand that you're doing it for the right reasons before moving forward with borates. ABCs of Pool Water Chemistry
 
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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
43,626
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Great to hear it is working for you.

Your acid volume needed will not lessen. Only the frequency with which you need to add the acid will change.
 
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chiefwej

LifeTime Supporter
TFP Guide
Jun 12, 2011
3,720
Tucson
My situation is very similar to yours, including the high TA fill water. I have been running 50ppm borates for a few years now. My pH will rise and stabilize at or near 7.8 for many days, (which still gives me a negative CSI) then suddenly rise. When it does, I don’t need a measuring cup. Acid additions are in half gallon increments! With borates the pH resist movement in either direction. That’s one of the main characteristics of borates in the pool water.
 
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Rattus Suffocatus

Silver Supporter
Jun 5, 2019
1,406
Corona de Tucson, AZ
Interesting.. my difficult last few months had literally piles of flakes on the floor due to lack of use and proper sweeping of the pool. My water has been okay, but my TA did get a little out of control at the end,. I have been hesitant to add borates because I find it impossible to keep my dogs from drinking to pool water (hey, it's salty!) ... but probably at some point I need to put a fence around it since the Golden Retriever (my one swimmer of the fours dogs) likes to tug on the now failing solar cover, and it's getting pretty ragged. If I fence off the pool from them, I suppose I can try the borates... but I didn't realize it would keep the "desert snow" from happening in the pool. The cell's been fine through all of this.. I probably only had bad CSI for a week or so... But the TA here is crazy in the summer.. like 170 or higher.... But interesting.. I seriously need to look into this...
 

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chiefwej

LifeTime Supporter
TFP Guide
Jun 12, 2011
3,720
Tucson
At the beginning of the season I use the acid and aeration method to drop the TA down to the 70 range.
 

Rattus Suffocatus

Silver Supporter
Jun 5, 2019
1,406
Corona de Tucson, AZ
I haven't figured out an effective way to aerate my pool yet. Honestly I should probably just run it through my utility pump and back into the pool, or through a garden hose back in from the spigot drain on the filter. I do aerate with my detached hot tub and it works fine because it's very easy to do. But I do need to do that... it was on the list of stuff to do/figure out at the beginning of the season that I haven't had a chance to do because of a string of family emergencies this year.

I swear there is more "rock" in the water here in Arizona than "water". It's really the only thing I have struggled with in the two years the pool has been online. Well I did have some issues this year with the pool overflowing because of 12" a rain in 6 weeks.. but that was fixable too. Though I need to find some more CYA unexpectedly.

But I am glad that I am not the only person to seem to have insoluble calcium flakes... I suppose when I was maintaining the pool properly, I swept them up enough not to really notice them, but they got bad when I didn't take the cover off for a month, that is for sure...
 
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