Thanks to everyone for creating the best Pool site on the Web. My poolís chronic Cheetah-like bottom/side stains appear to have been tamed to a great degree by following TFPís advice.
My situation/question: Iím at the one week post AA treatment point when the Ascorbic Acid is exhausted and FC has re-stabilized. After re-shocking the pool last night from 2ppm to 12 ppm (one week post AA treatment - great results), my pH naturally rose from 7.0 to nearly 7.8. Now, Iím concerned the pH spike may release metals.
Whatís a safe method to decrease pH quickly to 7.0-7.1 after a AA treatment / post AA treatment shock? Today, I precautiously added one pint of M. Acid mixed in 5 galís of water followed with sequesterant, about 1/4 of the recommended M. Acid dose by Taylorís test kit. No stains have reappeared after adding one pint of M. Acid.
Recent Pool history:
I keep my FL pool operational all year. On April 4th, I changed 1/3rd of the water to reduce an elevated CYA of 60.
After the water change, my pool had the typical Cheetah stains. Following TFPís CYA/Chlorine table, I shocked the pool to 20 ppm for one week while adding Poly60/sequesterant liberally, and brushed daily with a nylon Wall Whale brush. Filter cartridges are frequently changed. Persistent stains suggested metal staining, too.
On April 13, I treated metals with 1 pound AA/sequesterant (great results). I kept the FC at 1-2 ppm and waited a week to shock until the FC became stable, demonstrating the AA had finished reducing the FC.
Water temp: 76, Water clarity: Perfect, Bottom/Sides: Stain-free appearance, CYA: 30, FC dropping: 8, CC: 0, pH: was 7.0 yesterday. Now 7.8 (shocked last night liquid 8.25% bleach to 14 ppm), TA: 40, CH: 400
This April, Iíve used one quart each of Biodex and Suncoastís Ultra Metal Sequesterants, and have a 4-pack of the less expensive and recommended Blue Wave Super Rust and Scale to test soon. A 4-month old CUlator 4.0 was opened and stained greenish-blue and a new one added to the pumpís basket this week. It appears to collect free metals as advertised.
Added note: Myspicesage. com also has good prices on bulk, food grade Ascorbic Acid. The indoor storage life is said to be very stable. My 5 pound order arrived in one pound sealed packages.
A big Thank You from my pool to Yours.