Scale on one end of pool only

Rocket J Squirrel

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Bronze Supporter
Jun 7, 2018
959
Alamo, CA
My pool's water level is down an inch from usual thanks to a recent heat wave. In the pool today for the first time since the heat and smoke from wildfires, I noticed scale at the waterline on one end of the pool and a bit in the adjacent corner. Some of it won't rub off using my scrubby mitt.

What's different about this side of the pool?
  • It's the shallow end.
  • It's the north side. There's a tish of scale on the east side at the north corner.
  • It's where the pool cover doesn't quite reach to the end when closed.
My test results are in my profile. CH is 380, pH is stable around 7.5 and CSI has generally been between -.3 and +.3.

Fill water from the tap is:
FC 0
CC 1.5
pH 8.5
TA 50
CH 40
Salt 200

Pool School says pumice. Is there anything less messy to remove a line of scale? Should I replace some water to lower CH?
 

Rocket J Squirrel

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Bronze Supporter
Jun 7, 2018
959
Alamo, CA
Yes, while pondering this during my after-swim shower, it occurred to me this is the only end which isn't covered by the auto-cover. Who knew that auto-covers prevent scale on 3 sides of the pool?

Is there a recommended dilution of MA for this purpose? I have the 31.45% stuff. (And not sure what you meant by "etc.") Thanks.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,340
Laughlin, NV
Etc is pumice, scrapers, etc. Even saw some one use CLR. It is not as aggressive to your skin as MA.

I have used 5:1 with that strength MA. I now just not bother -------------:sneaky:
 

Rocket J Squirrel

Silver Supporter
Bronze Supporter
Jun 7, 2018
959
Alamo, CA

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,340
Laughlin, NV
Muriatic acid will have the same warning. They are right, do not mix liquid chlorine with acid. Your pool is 5 ppm chlorine. LC is 100000 ppm.
 

Rocket J Squirrel

Silver Supporter
Bronze Supporter
Jun 7, 2018
959
Alamo, CA
That is true, but I subsequently ran across this.

Can CLR be used on pool tile?
Unfortunately, we do not recommend using CLR on pool tile. It could remove the finish from the tile. In addition, if CLR comes in contact with chlorine, it could result in toxic fumes.
CLR® Pro Frequently Asked Questions

I'd be more concerned about ruining my tile than generating fumes. Oh well. Diluted MA it is.