Decided to try an experiment.
I was having a problem with my TA it was up near 190.
After reading much here, I decided to just try adding air to the water.
I went to the local pool store, looking for some type of in line air adding device. They didnt really have anything.
They called the shop "pool expert". He said I was just waisting my time and that adding air to the pool would not do anything. One persons opinion I thought.

So I found the most cost effective item I could get was a fountain that attached to the outlet
Ive been testing the water a couple of times a day for the past 3 days.

Day 1
FC7
TC7
CC0
PH 7.5
CYA 60
CH 250
TA 190

Day 2
FC 5 (added bleach)
TC 5
CC 0
PH 7.4
CYA 60
CH 250
TA 150

Day 3
FC 7
TC 7
CC 0
PH 7.5
CYA 60
CH 250
TA 120

Only changes have been the addition of the fountain and adding the bleach. Standard 10.5% solution.
Saw the ph drop to 7.4 on day 2 but then up again as the TA decreased.

Would the reduction in TA be a direct result of the addition of air, or could it be that the back pressure on the filter was increased by 3 mmHg by restricting flow from the outlet jet that the fountain is hooked up to?

Im thinking the added air is going to result in extra chlorine use as air is food for alge?

If you read the article about lowering TA, addition of acid lowers TA together with pH. Aeration raises pH without affecting TA. So, cycles of adding acid, and then aerating to bring pH back up will bring TA down.

Aeration alone, with no acid should not affect TA.

Did you test the make-up water? perhaps it is lowering the ph levels . when I airate I can get a ph of 7.2 up to 7.8 in 24 hours. I made a pvc connection with a econmical shower head I just screw into the polaris connection at the pool.

acid or lower TA fill water reduces TA...aeration, as was mentioned before, does not affect TA...only PH.

Hmmm here is this mornings test results

PH 7.8
TC 3
FC 3
CC 0
CYA 60
TA 100
CH 240
Phosphates 300
Water temp today 85
Earlier tests temp at 90

I am testing water from the same place each time. 18 to 20 inches below surface.
Testing at the same time each day
I have added no new water.
I have added no acid.
It has not rained this week.
We had 2 days at 88 degrees this week with high sun. First time it has been above 83 this season.
Only changes have been the addition of bleach earlier this week, and the addition of the fountain.

I do now see a slight rise in the ph but also see a drop in the TA (started at 190) now at 100 as well as a drop in the phosphates from 400 to 300

I am using the same test kit with all fresh reagents.
Not sure what to make of this.

Water is very clear

There is no item on the market for sell that does this that I could find. Might be a good patent

Stuart,

You said the changes you made were to add the fountain and add the bleach, so that implies that you were using something else to chlorinate the pool before. Were you using Trichlor tabs/pucks? Were they still in an inline chlorinator of floating dispenser when you were doing your fountain experiment? Even if this were the case, one 8-ounce Trichlor tab in 10,000 gallons would only lower the TA by about 4 ppm so nowhere near what you are seeing.

Normally when you aerate the way that you are doing, the pH will rise but the TA won't change. So what you are seeing is truly bizarre. You're sure you don't have some sort of automated pH controller on your pool?

Richard

Its been over 8 wks since I have used pucks. Pucks are the reason I started looking for a better way and found this forum. CYA was ++++++++
No inlines, no floaters, no automated gizmos. Just plain old chlorine bleach

If its not the ddition of the air, it almost has to be the increased contact time at the filter, because of the slightly increased jet pressures due to the fountain? although I dont think that the TA woud be reduced that much since the filter micron size remains constant.

Outside temp?
Pump running time has been same.
Increased sun time?
Have not had to add any extra water due to splash out, even so our tap water has a high TA and phosphates here.

At this point Im not really sure what is making it go down, but it is.
Today I had to add some acid to lower the ph, and chlorine, so this throws off the test.

Next time I have to add water, due to splash out etc.. Ill recheck and try again, Like I stated earlier our tapwater has a high TA and phosphates, so Ill try it again.
Nope I dont drink the tap water in S Florida. I dont suggest it to anyone.

he added acid to control his ph and that also reduced his TA.

That's only this last time, but previously he said "I have added no acid." so we have a mystery here. Either some strange test error or some unknown source of acid, most likely the latter since the pH didn't rise with the aeration yet the TA dropped -- a classic sign of acid addition combined with aeration.

Never figured this one out.
Now my TA stays at 90. Thats a major drop from the first result of 190
Only thing I can think of is when I spray off the concrete deck area there may be some "natural" acids that washed into the pool.
Using the fountain, I now see the increase in ph when used frequently but all my other numbers stay about the same.
Strange but TA has been good ever since this episode.