What to adjust first?

[julio]

Hello all,
I just bought a house with a pool (first time owner) last month and have now been reading the forum for a couple weeks (great place you have here btw). Just got my test kit today and did my first test. Took awhile since I read and reread everything, but I think I got it right, although the CH was really high... I was about to give up on the test and start over, but it finally turned blue. Here are my numbers:

FC: 4.5
CC: 0.5
pH: 7.5
T/A: 130
CH: 710 (might have mis-counted a drop or two, but it's close)
CYA: 90

The pool looks great, perfectly clear. Currently I have an inline chlorinator running with the trichlor pucks, but want to take it offline... Just need to get to the store to buy bleach.

Anyway, the CH and CYA seem to be the only items that are pretty far out of range. What should I attack first?

Thanks!

 

[Melt In The Sun]

Hi Julio, welcome to TFP! :-D

Probably not what you want to hear, but...with CYA @ 90 and CH @ 710, I would start by draining about 2/3 of the pool. That will deal with both at once. If you test your fill water's CH, you can get a better idea of how low your CH will go with XX% draining.

You can post some details (size, filter, pump, finish, etc) of your pool in your signature. At top of screen -> user control panel -> profile -> edit signature.

Edit: never mind, sig is there already!

 

[julio]

Thanks. Yeah, I knew I would have to do a partial drain to take care of the CYA. I'll try to test the fill water this evening and will post results when I have them. We have pretty hard water in central Texas so I suspect the number will be pretty high, but we'll see.

 

[julio]

Ok, had time to test CH of fill water and it came out at 210.

 

[ssa]

210 is not too bad. Agree with Melt In The Sun, partial drain to bring down CYA and CH.

 

[Melt In The Sun]

OK, based on 210 fill water, a 60% drain will get you to about 400 ppm CH (familiar with the pool calculator?). If it were me (and if your water's not too expensive) I'd do 2 2/3 drains to get CH down to about 300. However much you decide to drain, keep chlorine in it while you're doing it! The last thing you want is algae in a fresh fill.

 

[julio]

Thanks for all the info. I am familiar with the pool calculator, but hadn't used it much until now. Great tool, installed the iphone version last night.

Anyway, my next question... Is it safe to drain the pool this time of year? I've heard stories about plaster cracking and other bad things and I don't want to drain if there is a risk of anything catastrophic.