pH Insanity - Constantly Rising + Test Differences

[Shielamartin]

I've had my bromine-based tub for about a two weeks and since getting the pH, TA, CH, and bromine in line, I've had daily pH rises that I am unable to stop. I had 2 different kinds of test strips + a phenol red kit - typically the drops are showing a higher pH than the strips; in fact, often times the drops will show red/8.2+ (filling to the fill line + adding 4 drops + inverting as per the instructions) and the strips will show somewhere in the mid to high 7s. I had my water tested yesterday and it came back as follows:

pH: 7.2
TA: 73
CH: 127
Total Bromine: 5
TDS: 700

They suggested adding 9.75 tablespoons of SpaGuard Balance Pak 100 to hit their suggested TA of 125-150. My manual suggests that 80-120 is acceptable. I added 4 tbsp of baking soda, which increased my TA (it looks like it is around 80 now after more reducer was added). Checking the hot tub this morning, the pH is once again showing 8.2+ using the phenol red and in the high 7s using the test strip. This has been a daily occurrence over the past week, save for yesterday when I added baking soda.

I've heard people of both sides of the fence - get your TA in line and then adjust your pH vs. a low TA (60+) is fine, just control your pH. I do have an ozonator and noticed a decent amount of bubbles coming from the other jets when the filter runs. Could this be enough the be raising my pH daily? Should I try to spike my alkalinity by putting in ~10 tablespoons of baking soda? This will undoubtedly raise my pH a bit too, which could be brought down by using my pH reducer (using Aquarius pH Reducer - granular from Canadian Tire), but I'd rather not add a pile of both substances if it is not necessary. Or am I doomed to needing to add pH reducer on a daily basis?

[Red MC]

Hi,

I put your test numbers into the "watergram" balance calculator wheel that came with my Taylor test kit:
pH 7.2, TA 73, CH 127

Assuming a water temp of 100 deg (a guess), it suggests you're too acidic, so it's possible you're fighting to pull it in the wrong direction.

With calcium hardness of 127, I'd add total alkalinity increaser until TA hits 100-120.  Then check your pH.  Your water will be in balance at a pH of 7.5-7.6 and 100F.  You can use some pH increaser/decreaser to get it in that range.  In my experience, that's a relatively easy balance to maintain with a dose of alkalinity increaser once every week or two.

It's important to have an accurate pH test.  Next time you bring in a sample to be tested, use both your test strip and the dropper test on the same water, and compare results.  That will give you an idea of which is more accurate.

The problems I've had with remaining water balance have been soft or hard water.  I've had water come out of the tap with a calcium hardness of only 20-30, and as much as 200.  The former makes it hard to keep pH up, and the latter makes it hard to keep pH down.  When I fill, my calcium hardness is usually on the low side, so I use calcium increaser to get it roughly around 100.  When calcium is high, you can try using a stain & scale reducer (aka an acid blend).  I'm not exactly sure how it works, but I think it causes some of the excess calcium to precipitate out and then get caught in the filter.