Acidic fill water?

[Isaac-1]

While testing my pool water earlier today I decided to run a test on the fill water since I had not checked it in a couple of years (water source is a private well) and I found the water was considerably more acidic than the last time I tested it.

Here are the overall numbers:

pH <=6.8
TA = 30
CH= 40
No known detectable metals

I ran the pH test twice, once with 2 year old pH reagent then again with fresh from my new TF-100 resupply pack, using pool water with measured pH of 7.5 mixed 50/50 with tap (fill) water I extrapolated a pH of 6.7 - 6.8 of course there is a large margin of error, but this should at least show the pH is not insanely low. The last time I tested the pH a couple of years ago it was 7.0, we did have a severe drought last summer followed by lots of rain over the winter and spring this year, I am not sure how much this effected the local water table though. Does anyone else have similar acidic fill water experience? I have not noticed any big changes in pH stability lately, but also don't know how long this condition has been present.


For completenes sake the pool test showed:

FC=4.0 (still tuning in the chlorine pump for warmer water now that the new roof is on)
CC=0
pH=7.5
TA = 60 (was 70 a week or so ago)
CH=160
CYA = 20 ( target is 25-30 added my last pound or so of stabilizer should boost it by about 4ppm)

Ike

 

[JasonLion]

Since the fill water TA is low, it's PH doesn't matter all that much. The much higher TA water in the pool will dominate the final PH. Because of that, your estimate of the PH of the fill water is going to be off, the actual PH must be much lower than you estimated.

 

[Isaac-1]

Do you have any suggestion on how to get an accurate pH reading on the fill water?

Ike

 

[JasonLion]

There are any number of ways, but none of them use things you are likely to already have. There isn't much point in knowing the exact PH, with the TA that low, it really doesn't matter much as it will change at the drop of a hat. The PH is also going to vary over time, most likely seasonally.

 

[Isaac-1]

I may talk to my brother in law about testing it, he is the lab maganger at the state charity hospital about 50 milea away.