Lowering TA, 1st Round TA Dropped, 2nd Round TA didn't. Why?

[Flipmode]

Salt Water pool
70,000 Liters
Salt=3200ppm

Before Adjusting
FC=2.0
CC=0
PH=8.0
TA=230

1st Round of Muriatic Acid (3 Litres), No aeration yet
FC=3.0
CC=0
PH=7.4
TA=180

2nd Round of Muriatic Acid (3 Litres), Added Aeration, plus added CYA in sock for slow dilution
FC=3.0
CC=0
PH=8.0
TA=180

1st round dropped TA by 50 PPM, 2nd round did not drop it by any.
Pool has circulated for 8 hours between tests.

I never seen this happen before, is there a logical answer, could it have something to do with adding CYA?

I started the 3rd round (3 Litres) tomorrow I will test again

Thanks

 

[duraleigh]

Re: Lowering TA, 1st Round TA Dropped, 2nd Round TA didn't.

It's not a perfectly smooth path but it will work. Rounds 3,4 or whatever it takes, it will work.

 

[Flipmode]

Re: Lowering TA, 1st Round TA Dropped, 2nd Round TA didn't.

Ok thanks Dave,

I have been helping my neighbors and friends and this
Is the first time this has happened. With not having
A logical answer it left me looking like I didn't know
What I was doing.

I guess we will caulk that up to it happens.

Cheers