Up & Down TA

[JulieS]

What are some factors that cause the TA to go up after adding acid to make it go down? I have been struggling to keep my TA in range, and this morning I have made it down to 110 again, my goal is to get down closer to 80 but I am going slow as not to crash my pH or over shoot my mark. However, it seems that every time I get in range, it shoots back up to 170-180, and I cannot figure out why!

Any ideas?

(Using constant aeration to help maintain proper pH, pool is crystal clear)

Today's readings (Using the HTH 5 way test kit):
CL - 3
pH- 7.3
TA-110 (added 9oz of pH Minus after this test)
CH- 260
CYA-25

 

[JasonLion]

Are you adding water to top off evaporation? Fill water often has TA in it.

 

[JulieS]

Only once a month ago did I add to make up for evaporation. This rise and fall of the TA has been occurring for two months! The HTH people told me to keep adding pH minus and not worry about the actual pH, and it tanked down to 6.5, and still my TA was going down only to 120 then the next day it would be 170. I didn't trust my test kit, so I started taking samples to the local hardware and having it tested on their computer, and it showed the same thing I had at home. Then I found this site and learned about aeration, since then I haven't allowed my pH to drop below 7.2. I have been aerating until I reach 7.8, then adding the pH minus to lower the TA. It comes down on average 10-20 ppm/day, then shoots back up to 170-180. Today is the lowest it's ever been at 110, and with my pH at 7.5 I felt comfortable adding another dose of pH minus, as I'm trying to get down to a TA of 80. I am just afraid that when I test later, it will be back up to around 170! I can't figure out why it keeps shooting back up! I'm hoping it's something that I can prevent or correct to keep the TA in check ALL the time!

 

[aa62579]

As a quick question, why are you so concerned over your TA? How quickly does your pH rise when you aren't adding aeration?

 

[JulieS]

My pH rises very slowly without the aeration. I was told that a high TA can cause numerous problems with the pool, for the equipment and swimmers. Everything that I read tells me that I should keep my TA between 80 & 120. Am I wrong?

 

[aa62579]

I wouldn't worry about it then. Concentrate on your pH and just add acid when it gets high.

A higher TA just means your pH is less stable and can cause a higher CSI. This could cause plaster issues or scaling - not really too big of deal with an above ground pool.

 

[JulieS]

I appreciate your response, I will take your advice! However, I am still looking for reasons that my TA is going right back up after I get it into range. My pH is stable and holds at 7.2 unless I aerate to increase it when I need to add the acid to lower the TA. I have a vinyl pool, but a similar pump to you. I have read that a high TA can cause damage to the pump, not to mention the eye irritation, and skin issues. There is so much information on the net these days, it's hard to know what to believe! I will go with what you say as it looks like you are speaking from first hand experience (your signature says fighting high TA)!

 

[aa62579]

My TA starts out at 325 - 350. I'm at 250 now. Don't expect it to get much lower than that.

A high or low pH can certainly cause damage, although low is much worse. I've not seen it anywhere on this site (or elsewhere) that a high TA can damage the pump. The eye or skin irritation would be from the high pH, not the high TA itself.