TA is on the rise. Loath muriatic acid.

[8corneflakes]

What makes TA go up?

My TA has risen to 190...again. A couple weeks ago, I got it back down to 130 and it is on the rise again.
pH has also risen to 8.2

Looks like it is muriatic acid time again. Last time, I did a horrible job of trying to change these numbers. I ended up with a pH that was dangerously low. With these numbers, the calculator says to add 159 ounces of muriatic acid. That seems a bit high.

Advice...ready, set, GO!

 

[BethyM]

Did you top it off with fill water? What is the TA of your fill?

I tend to add my acid one gallon at a time, at the most, and then retest. That's all the advice I have, sorry! I'm super excited to have gotten mine down to 300 from 550 especially with so many top offs in the heat.

 

[8corneflakes]

UGH, just tested it. Fill water has a TA=300. Ouch. That's our problem. Oh well, we do like to swim.

 

[topher]

just out of curiousity what is your CH from the tap? mine is almost 400 so i am stuck with high CH forevor

 

[8corneflakes]

my tap water tested CH to be 20 pm. how can that even be correct when the kit says that 200-400 is ideal? It only took 2 drops to turn it blue. Don't you just hate when you start out with something that isn't ideal? We chose pond water over high iron content water, only to discover that our pond had copper in it from algaecide. In hindsight, I should have done a rock-paper-scissor test with iron and copper to see who would win.

Of course it would help if we could get more than a teaspoon of rain this summer.

 

[BethyM]

I'm convinced we can deal with the high TA from the tap (have to be, or I'd be crying a river ) But it does mean we'll be using acid. This is my theory, and it may stink but I'll try it out on you anyway

I'm going to have to add acid as long as the TA is high because of the pH drift.
If I have to add acid, I can also add the additional steps of a) lower it to 7.2ish and b) aerating in order to drive the pH up faster.
This will cause me to add acid more frequently now to control pH but will also also allow the TA to drop faster than acid additions alone.
GOAL: Eventually, the HUGE body of water will have a low enough TA that the pH will stabilize and reduce the need to add acid as frequently. TA will increase slightly over time because of the fill water but hopefully not ever get to the crazy place it is now. Lowering the TA in the large body of water is 'easiest' in the long run as long as there isn't a major drain required.

That's how my mind sees it... I'm stuck with the acid for now, but hope to see 'stable' happen eventually. You didn't say how old your pool is? (Keep in mind, i'm a noob and you may want to ignore my advice completely :lol

 

[8corneflakes]

This is my theory as well. I just messed up the 1st time using muriatic acid and dropped my pH down to 6.7. Scared me. We have deck jets and a slide fountain so our pH rises really fast too. Plus, a minimum of 10 people splashing all day.

This is our 1st swim season because we spent all last summer building it. We did have an AGP before this one and used BBB on that one too. We didn't have TA problems with that one because we had the city fill it up. THis pool is just too big to have water trucked in.

 

[Bama Rambler]

Be sure you have the TA & pH correct when entering them in the Pool Calc. Also add about 3/4ths what the calc suggests and test again.

 

[chem geek]

my tap water tested CH to be 20 pm. how can that even be correct when the kit says that 200-400 is ideal?

A CH of 200-400 is for plaster pools. You don't need CH for vinyl-lined pools (assuming they don't have any exposed grout in tile or anything like that). Usually high CH and TA go together, but not always. "Good" tap water that isn't too hard usually has CH well under 50 ppm and TA that is in the 50-100 range. A pool-level 300 ppm CH in tap water is not a good thing.

 

[8corneflakes]

so my tap ch is fine, but that doesn't even matter. But my tap TA...bad water, bad! I will have a no splashing rule from this day forward.

 

[Sportsman]

My tap is very high TA and I had to add MA weekly at first. Over three years it's probably now monthly and I've actually had to add baking soda to bring my TA back up to around 70 (pucks got me during a two week vacation).

I just learned that approximately a third of a gallon brings my pool from 7.8 to 7.2 and I pour straight from the jug to the pool which is by far the easiest way to handle the acid. Occasionally I've overshot it but I just adjust the return to aerate for a while and I'm back in action. That's only happened a couple times.

 

[Swampwoman]

Bethy, if you sustain frequent drops to 7.2 while agitating to raise the ph (eg a fountain) you may be able to get ahead of the TA curve more quickly. Mine wasn't as high as yours, but I got down from 180 to 70 in a little more than a week.
I still have to add acid about every 10 days (I leave the jets facing upward to cause the leaves to flow to my skimmer before sinking, which increases the ph rise) but things behave much better at the low TA.

So yes, your mental image is correct, but the speed of accomplishment can be much more aggressive than "eventually" because you want to outrun your need to replace water