CH jump

[reebok]

my CH went from ~400 (for months) to 600 in less than a week. I added maybe 1.5" of water to get the level back up a bit, and removed the pool light from the niche, but beyond that I can't think of anything I've done recently (except remove the trichlor tabs, but that's been a few weeks). yesterday I did the test twice and quit both times because it wasn't changing color. today I decided to go and go and go and finally it changed at 60 drops. so my ta is too high and my ch is too high, of course I have the problems that can't be fixed without difficulty (i.e. aeration or replacing water but we're in a giant drought). anyhow, the main thing I'm wondering is how/why my calcium jumped so high. my first test was 400 on 5/2 or so, and like I said the pool store has been telling me 399 for a months. the water I added is the same water used to fill the pool in 12/2007 (new plaster). the only thing I can think of is if the house water softener recently ran? I don't even remember exactly what that does, but I think it has to do with sodium and calcium ions. my other numbers are below.
FC 8
pH 7.6
TA 200
CYA 70
CH 600

 

[duraleigh]

my CH went from ~400 (for months) to 600 in less than a week.

Two possibilities and only two......testing error or you added some calcium in some way. Testing error seems likely.

You didn't ask but your pH is too high. I suggest you lower it as soon as you can down to about 7.2 or so. It'll also reduce your TA. :lol:

 

[reebok]

I wonder if my error was my first test at 400 because I expected it to be that. Cause 3 times now I've verified its over 500 with 2 kits and the 4th test today I finished it out and got the 600 reading. Also, I've battled rising ph since my pool was redone, and the other day I accidentally dropped it to 7.2. Its made its way back up to 7.6 now, but I don't really want to go back down because it burned my eyes at 7.2. Can you give me some more info on why it should be low? If you mean just to lower TA with aeration I get that, but I was waiting to do that until I add borates. Out of curiosity, if I add them without lowering TA, will I still get the algaestat and sparkle factor? Thanks.

 

[PaulR]

Borates will make it harder to move the pH, which will therefore make it harder to reduce your TA. Get the TA where you want it first, then do the borates.
--paulr

 

[duraleigh]

Can you give me some more info on why it should be low?

High pH ( over 7.8 ) plus your high CH is setting up ideal conditions for calcium precipitation (scaling). Keep you pH in the 7.'s

 

[Guest]

Also, your high TA is the reason that you are having problem keeping your pH from rising too high.