Numbers from my pool - looking for input

[TFPJules111]

From my first test with the TF test kit on 8/22/07 - keep in mind my filter was broken, we'd just moved in to the house, and the previous owner was using trichlor tabs in a floating feeder.

FC .5
CC .5
TC 1
pH 7.2
TA 120
CH 1160
CYA way way over 100
Temp 85

Numbers from 9/25/07 - after new filter, several partial drain & refills ($200+ water bill - OUCH!) & BBB method

FC 6
CC 0
TC 6
pH 7.5
TA 100
CH 340
CYA 60
Temp 82

The water is clear & sparkling, no chlorine smell.

According to Jason's pool calculator, I have a CSI of .34

When I run the polaris cleaner overnight, I'll often find 1 - 1 1/2 cups of white, grainy material in the bag in the morning. I'm wondering if this could be due to the high CH, or if it's just bits of my pool's finish that are coming off.

The pool is about 20 years old, and there appears to be a piece of rebar showing through the finish in one spot. At first I thought it was just a stain, but I put on a diving mask and went down to have a look. I could see fuzzy tendrils of rust on top that brushed away with my hand and can also feel where the finish is missing.

 

[JasonLion]

Congratulations on the dramatic CH and CYA reductions and clear water!

When I run your most recent numbers I get a CSI of 0.05. Perhaps there is a typo in either the numbers you posted or the numbers you entered when calculating the CSI?

If the plaster is 20 years old it is not surprising if it is failing. That would fit with rebar showing through and bits of plaster showing up in the cleaner. Even significantly newer plaster could have the symptoms you describe with some bad chemistry at some point in the past. You can probably get away with leaving it as is for quite a while but eventually you will have to look at replastering.

 

[TFPJules111]

When I run your most recent numbers I get a CSI of 0.05. Perhaps there is a typo in either the numbers you posted or the numbers you entered when calculating the CSI?

D'oh!

You're absolutely right. Last night (when I ran the numbers through your pool calc) my pH was 7.8 so I added acid & retested this morning. My current CSI is .05.

What does replastering entail? Do they spray / apply the new over the old? Or is the old removed first?

PS - I'd been meaning to make a donation for the poolcalc, since I use it several times a week. Look for a contrib from me today.