Blue scale in salt cell

Sendero

Member
Jan 22, 2017
5
B.C. Canada
I installed a Hayward Aqua-Rite low salt generator in my pool in June of this year. Yesterday the “check cell” light was flashing so I took it out for inspection. The plates in the cell had quite a bit of light blue scale some of which was a good size. I should note that the previous Hayward SWG it replaced never had any scale buildup at all.
I tested the water today, the results are below. I add nothing to the pool except chlorine occasionally & muriatic acid.
FC- 4ppm
PH- 7.7ppm
TA- 80
CYA- 60
Calcium- 90ppm
Salt- 2100 ( a little high, recommended 1800ppm)
Does anyone have any idea what this might be or what caused it?
41837C34-E9D6-4C53-988E-9B01BD36DB3D.jpeg
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,056
Laughlin, NV
Your data does not imply scale should occur but I do not know if the low salt version makes a difference. Typically, by lowering the TA, you should reduce the amount of scale created.

Blue color implies copper in your pool water.
 

Sendero

Member
Jan 22, 2017
5
B.C. Canada
I put the piece of scale in the acid & it fizzled a little & dissolved slowly . I think the fellow who opened the pool back in April added some algaecide with copper but I thought it would have dissipated by now.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,056
Laughlin, NV
Copper does not dissipate. It is in the water until you drain it.

Sounds like a calcium silicate or other calcium compound.
 

Sendero

Member
Jan 22, 2017
5
B.C. Canada
Thanks. Good to know about the copper. Living in the Great White North the pool will be only be open for another 4 weeks max so I’ll see how much scale has accumulated at closing.