Hey.... I just replaced 2/3 of my pool water (23K gal in Dallas, TX) and successfully reduced CA from 538 to 265 (source has 110) and CYA from 115 to 45.
I've been noticing over the past 6 months (pool keeper quit and I've been learning ever since.... I suspect that he had been using a sequestrant) that the gunite surface is staining (started on steps and now is noticeable on walls and floor). When I started draining the pool I finally tested the stains with Vitamin C tablets and, sure enough, the stains disappeared instantly and completely. However, without thinking I continued to replace the water and now I'm realizing I should have lifted the metal off the pool surface with an ascorbic acid treatment BEFORE I removed 2/3 of the pool water.
So here's my question.... Did I get rid of most of the metal (i.e. still suspended in the removed water) or was most of the metal retained (i.e. still stuck to the walls)?
I kept a sample of the old water so.... I'll test the metal content in 1) the original water, 2) the new water, and 3) the water after doing an ascorbic acid treatment.
I'm hoping that test 1 is high, test 2 is low (i.e. the source water is low), and test 3 is also low (i.e. I didn't retain most of the metals by not removing them from the walls before replacing the water).
I will post the results ASAP. In the meantime.... what do you experts think I'll discover??? Also.... what's the best way to test for metal content (i.e. should I trust the pool stores or is there a more reliable place to test)???