My old single speed pump stopped working last month and Leslie's installed a new Pentair Variable speed pump for me. Currently it is running at highest speed from 12 pm to 5 pm and at just skimming the surface at other times. The pool had turned green while the pump was not working. I got it back to blue. A few days later it agained turned green, (we had a couple of thunderstorms and heavy rains) right before the long weekend. The CYA when tested was zero, so I added 7lbs to the skimmer (should raise CYA level by 60 by my calculation) and then followed SLAM process. A week later CYA was registering in 30-40s and pool was a murky gray with lots of turbidity. Since a week had passed since adding CYA I backwashed to get the pool crystal clear. 3 days later, bam CYA back to zero and a green pool. The extremely high temperatures are not helping. This has never happened before when i used to keep my old pump running for 24-48 hrs after SLAM process and adding CYA. So I'm worried that the new pump is affecting the process.
Here are my questions:
Will the speed running at highest level for just 5 hrs significantly decrease the CYA dissolve rate? With old pump, I backwashed after a week with no issues. Should I give more time between backwashing for variable speed pump? Then I get into the pool not filtering adequately conundrum. Should I use the CYA sock method? Does the CYA dissolve when the water is just passing through the filter at lowest rate?
The cleaner works only when pool is at highest speed setting. Is that significantly affecting the cleaning rate? Can I put cleaner to work when pump at lowest speed?
Previously I have always got my pool back to blue in 48 hrs and this is really worrying me.
Also how do I proceed now?