Need advice on what to add as I slowly reduce my CYA

[another one]

Ok, so for the past 4 weeks I've been draining water to reduce my CYA (indoor pool, and I've been listening to the pool store guys and letting them do my testing).

when I started draining my levels were (from my TF-100):

pH - 7.5
FC - 16.5
CC - 0.5
TA - 175
CH - 300
CYA - 60

I'm draining around 700 gallons per day (missed a few days), and so far I've drained 14,000 gallons, which according to my spreadsheet means the pool has 40% new water, and 60% old water.

My levels today are:

pH - 7.8
FC - 2.5
CC - 0
TA - 65
CH - 150
CYA - 35

My CH has fallen by 50%, TA by 65%, and CYA by 40%. Along the way, the only things I've added is 9 lbs of calcium chloride to get the CH up and 1 quart of 31% muriatic acid to help lower the TA.

So when I add bleach today to get the FC up to 4, should I try to adjust anything else? By my calculations, I still need to drain about 10,000 more gallons to get the CYA down to 25 which will take about 2 more weeks.

PS - pool calc says I should add 33 lbs of CaCl to bring CH up to 250, real question is should this be done now or in two weeks.

 

[duraleigh]

The pH could be lowered if you like. It's in the normal range but the top end of normal. Other than that, everything looks fine. How does your water look?

 

[another one]

Water is perfect, my wife commented last night on how there was no chlorine smell whatsoever.

I think the pH is up because we've been using the spa, the well water pH is around 7.5.

 

[another one]

Last question:

I plugged in the desired pH level into the pool calc and with FC 4, pH 7.5, TA 60, CH 150 and CYA 35, the CSI is -0.46 which says "Potential to become corrosive to plaster". Do I have to correct this by raising CH?

 

[Bama Rambler]

In a plaster pool your CH needs to be higher anyway so that's the correct thing to adjust. I'd bring it up to the recommended range listed in the Pool Calc.

 

[another one]

Thanks, I'll bring it up to 200+. I'm trying not to add too much that I'm going to drain away anyway over the next 2 weeks, but now that we have a working heater, and it's going to be 90 degrees for the next 4 days, we'll be using the pool a lot. :-D

 

[Melt In The Sun]

Are you done replacing water? I would wait to add the calcium til you are. I don't think -.46 isn't low enough to cause damage over that short amount of time.

 

[another one]

Not done replacing yet, two more weeks at 700 gallons per day. My well pump runs as much as my pool pump.

 

[Isaac-1]

What CYA level are you shooting for? I maintain my indoor pool at a CYA level of 20 ppm, just because the advice around here is some CYA is good, and the common test only read down to 20ppm.

Ike

 

[another one]

I'm shooting for a CYA of 25 for now, this winter, if we stop using the pool for a while, I'll drain some more water and try to get it down to 20 which seems to be the recommended level.