Buildup on time

[Tbooux]

Have had my pool up and running for almost a year now and hove a white buildup forming on the tile line. It’s very hard and need a knife or screwdriver to take off. Any idea what’s causing it and what’s best way to clean?

 

[Tbooux]

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Timmys pool
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Build Type: Plaster
Volume: 25000 gallons
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Latest Test Result Summary:
FC: 4.0 (20 days ago)
CC: 0.5 (20 days ago)
pH: 8.0 (20 days ago)
TA: 50 (20 days ago)
CH: 375 (20 days ago)
CYA: 70 (20 days ago)
SALT: 3000 (20 days ago)
TEMPERATURE: 83° (5 months ago)
CSI: -0.10 (20 days ago)
==========================================

 

[ajw22]

Looks like waterline scale. Is it around the entire pool or just the spa spillover area?

Waterline Scale Removal - Further Reading

www.troublefreepool.com

 

[Turbo1Ton]

Also, do a search for efflorescence. It is a little bit different than the waterline scale, in how it forms.

--Jeff

 

[Tbooux]

It’s more around the spillover but starting to see a little bit all around. What’s causing it, is there anything I can do to prevent?

 

[Rocket J Squirrel]

Your CH is moving around a lot but generally rising. Even though it's still within limits at 480. Are you using cal hypo to chlorinate? If so, maybe switch to liquid chlorine?