CSI and tile water line calcium buildup

[swamprat69]

Recently had a failure of autofill valve and noticed it had popped up and overfilled the pool. Pool filled to within an inch of the top of the skimmer. Reseated autofill at a lower level and shut off autofill feed. With the pool level above the accumulation at the tile waterline can I try to hold a lower PH to keep a lower CSi and possibly help with the calcium at the tile line until the pool level returns to normal?

 

[mas985]

Yes, but it is an extremely slow process unless CSI is extremely low <<-1. Here is chart of theoretical plaster erosion rates which are based upon a few measurements and should be similar to scale although scale should be a little faster.



Reference measurements shown here:

The CSI is Reliable for Plaster-based Pools

So was the same setup (i.e. coupon size and water volume) used in both experiments? Yes. I look forward to your analysis. Maybe some day I will conduct a more specific comparison. Obviously a big improvement would be to use the same time period for the experiment.

www.troublefreepool.com

 

[swamprat69]

I can see that CSI would need to be extremely negative and PH would probably kill my heater.

 

[mas985]

Some have used a heater bypass to temporarily run very low PH/CSI water through the system for a no drain acid wash so it is possible. But even then, it can take several days.

The Zero Alkalinity Acid Treatment

The concept of the “Zero Alkalinity” process (also known as a No drain Acid Wash) is to make pool water aggressive enough (by adding acid) to dissolve and remove metal stains or calcium scale from cement-based plaster surfaces, including quartz and pebble swimming pools. Unfortunately, this...

www.troublefreepool.com

 

[sande005]

Or wait until the water drops below the line, and scrub down with a blue gentle dish scrubbing sponge and straight white vinegar if the buildup isn't too heavy. Rebalance pH after, but it may not change much.