Constant Low TA, High PH

[like2lean]

The whole BBB system works very well for me, but it seems like I constanly fight low TA and high PH. The lowest I've dared let TA sink is 50, 8 lbs of baking soda puts me back to 100 for a few weeks. The PH always wants to be high, I add acid about 2 times a week to control it. Is this normal for a 1 1/2 year old 16k gunite pool?

FC-3-5
TA-90
PH-7.5
CH-270
CA-50

My water is always clear, I've only shocked it once this spring when I opened it. It all seems very easy, just that these 2 readings can't seem to get along. It's been that way since new, so maybe thats just the way it's going to be. The real question is: how low can I let TA go? I never have any problems correcting PH so why does it matter?

 

[jblizzle]

This sounds a little different to me. Usually pH will rise more with higher TA. And people try to lower their TA so that pH does not drift up as fast.

Do you have a constant source of aeration (waterfall/spillover/etc) that would make pH rise more quickly?

 

[JasonLion]

You shouldn't raise TA that high and you shouldn't lower PH very low. If you keep the PH near the high end of the range and the TA near the low end of the range you will have much less PH drift. I suggest you keep TA between 60 and 70, and PH between 7.5 and 7.9.

Do you have a fountain, waterfall, deck jets, or other similar water feature?

 

[like2lean]

I do have a waerfall, but we don't use it that much. The 7.5 ph is at the low end now, I just added acid, again. My real question remains, if I don't have any problems keeping PH in range without all the wild swings you read about, is there any other reason to keep TA in the conventional proper range of 80-120? Has anyone experimented with it say at 30? Would there be any other ill effects?

 

[JasonLion]

There is never any reason to keep TA between 80 and 120. That isn't an appropriate range for any pool. If you look at the recommended levels chart in Pool School you will see that we recommend 70-90+ for most pools and 60-80 for SWG pools.

The TA level has no direct effect on anything. It's importance is in the way it helps buffer PH changes. As a general rule it isn't a good idea to let TA go below 60 unless you have added borates to the water. With borates you can go down to 50, or perhaps 40, because borates help buffer PH in addition to the buffering from TA.

When TA is too low the PH will change drastically with every chemical addition, leading to the risk of pool damage (if PH goes too low) to metal staining or calcium scaling (if PH goes too high). Low TA is also a problem if you are using dichlor or trichlor. Both are acidic, and without the additional PH buffering of relatively high TA levels either one will drive the PH down to low far too easily.

 

[linen]

There is never any reason to keep TA between 80 and 120. That isn't an appropriate range for any pool. If you look at the recommended levels chart in Pool School you will see that we recommend 70-90+ for most pools and 60-80 for SWG pools.

This might be coming from the poolcalculator, when goal levels are set to "Traditional Pool".

@liketolean

If my above statement is correct, we would suggest you use "TroubleFreePool.com" in the goal levels setting in the poolcalculator.com

 

[like2lean]

There is never any reason to keep TA between 80 and 120. That isn't an appropriate range for any pool. If you look at the recommended levels chart in Pool School you will see that we recommend 70-90+ for most pools and 60-80 for SWG pools

Roger that, but the rest of the world reccommends 80-120. I've learned all I know from this forum and the most excellent pool school. I've kept my TA between 50-100, usually 60-90 (per the pool school) I just don't understand why it constantly moves, what the influences are that require constant correction. I thought it would eventually stabilize.

 

[JasonLion]

Any change in PH wil change TA. And PH is always going to be constantly changing. Most chemical additions affect the PH, and thus the TA. That said, things can be adjusted so TA doesn't change a whole lot, and the key to that is to never raise your TA as much as you have been doing. Let it settle right near the minimum and only raise it a little bit when it gets to low.