Finding balance: High CH & TA after refill, PH keeps climbing


New member
Jun 3, 2015
Paso Robles, CA
Pool was recently refilled with (very hard) well water (long story). When I got back last week, “pool guy” said he “balanced and conditioned” it. I checked the chemistry Friday morning & got these numbers:

TA 220
CH 170
PH: 7.6
FC 3.5
CC 0
CYA: <20

I’ve been checking it daily & adding liquid chlorine and MA as needed. Tonight’s numbers looked like this:

TA: 230
CH: 275
PH: 8+
FC: 2
CC: .5
CYA: >20, <30

Not sure if the TA/CH variations were my imprecision or actual changes. The PH definitely is spiking between treatments.

The pool’s uncovered in full sun and it was over 100 out today. Water temp is around 80.

Pool guy insists that “everybody” uses “tablets” here because of the hard water. But that route led to sky high CYA levels a few years back and a mess. (And then I found y’all at TFP…)

Since the CYA levels are still pretty low, using the tablets in the chlorinator and float for now doesn’t seem unreasonable, and should help push down the PH, right?

Will using Trichlor tablets in the chlorinator & float affect the CH?

Is it just a matter of having to keep adding acid until it comes into some sort of equilibrium?

Are there other things I can/should do to keep things from going South? Things that I should definitely *avoid* doing? (Other than adding Cal Hypo--that is clearly *not* what it needs.)

I was supposed to be done with this house and this pool and my primary concern is keeping it looking good until it’s sold (with the minimum amount of time and $$). But being able to swim takes a bit of the sting out of having to deal with it. ;-)


Platinum Supporter
TFP Guide
Jul 30, 2014
Monmouth County, New Jersey
How did you CH go from 170 to 275? Raise your CYA to 50 as you will burn less chlorine off given the extreme temperatures in California. You can use tablets short term to raise CYA to 50, and your PH will drop naturally as 3" tablets are acidic. With TA of 220, it will take some time before you have stable PH. Once your CYA gets to 50, switch over to liquid chlorine. Maintain your minimum FC levels based on your CYA as well.

Once your CYA reaches 50, keep good notes to determine how your PH behaves. If your PH gets to 7.8, drop it to 7.2 and see how long it takes to climb back. This way, every few days, based on a schedule you will have some idea on what to add. I had rising PH issues that took about one year to adjust. Every 4 days, MA would be added. I went from 120 to 70 before the PH stabilized (pre SWG). After the SWG, and higher CYA levels I was able to keep my PH in check as well. As an FYI, CYA also has and is important to manage as it will help you control your PH.


New member
Jun 3, 2015
Paso Robles, CA
Thanks for your responses!

I suspect "testing error" accounts for the change in CH--I got a reading of 200 this morning.

It *has* scaling issues and if I was going to be here long term, I think that actively trying to lower the TA would be worth it. As it is...I'm inclined to go with using trichlor tabs until the CYA comes up to manage the chlorine consumption and ignore the TA level, at least for now. If I'm bored next weekend, maybe I'll MacGyver an aerator.

I think my takeaways are:

1. Monitor the CYA level and quit using the tabs once the CYA comes up (to no more than 50) .
2. Accept that it's going to keep eating chlorine and MA for the time being.
3. A pool is a hole in the ground that you dump time and money into.

On the positive side, it's prime swimming season and the water feels great. :) Perhaps swimming more laps will help relieve the aggravation...


Mr Bruce

TFP Guide
Mar 24, 2014
Greenville, SC
With a TA that high, you may not have to do that much additional aeration. Jets breaking the water, wind, swimming, robots etc all count as aeration. If you keep lowering pH to 7.2 often you might be about to knock it down quite a bit.