Muriatic acid lowers TA, or does it?

[frustratedpoolmom]

I pretty much understand the concept but ... pH level in my pool is always going down, not up. And TA is at a 100.

Does it mean I need to raise TA more ? I thought that pH dropping is normal and this is caused by rain and chlorine.

PH is going down? That's usually a result of using trichlor or dichlor, which are acidic and lower PH and raise CYA. If you use/used these products that would explain it.

 

[chem geek]

It's unusual for the pH to go down as was just noted unless acidic source of chlorine are used or if non-chlorine shock (MPS) is used (it's also acidic). If you find that the pH tends to drop, then raising the TA level will help assuming that your pool is uncovered so that carbon dioxide can then outgas.

 

[iskubits]

I am using liquid chlorine. My neighbour is using pucks and his pH always goes up. Go figure ...

 

[frustratedpoolmom]

I am using liquid chlorine. My neighbour is using pucks and his pH always goes up. Go figure ...

Well if his TA is extraordinarily high and he has a source of aeration, that would make sense too.

 

[poolguy575]

I remember 20 years ago in my boiler water treatment days, we had issues on occasion with high alkalinity refresh water. We used a process called split-stream degassification in which part of the water was diverted to a unit that used aeration to lower the alkalinity. Muriatic acid was metered into the stream which trickled down a column with forced air bubbling up in a counter-current flow. This stream now with a low alkalinity was reintroduced to the refresh water. The amount of alkalinity reduction was related to the fraction of the refresh water that was being diverted to the degassification unit.

I don't have problems with high alkalinity in my pool, but I have offen wondered if someone could reduce the amount of acid they were using to lower alkalinity by diverting some of their recirculating flow into a cascading waterfall where acid was added just to lower the local pH to below 7.0 to accelerate off gassing of CO2. I'm thinking one might get more bang for their buck.

 

[JasonLion]

poolguy575, welcome to TFP!

Since it is the acid that actually lowers the TA, and then aeration raises the PH back up, using a degasification column can speed up the process, but it won't reduce the amount of acid you need.

 

[Guest]

I pretty much understand the concept but ... pH level in my pool is always going down, not up. And TA is at a 100.

Does it mean I need to raise TA more ? I thought that pH dropping is normal and this is caused by rain and chlorine.

what are you chlorinating with? Are you using any non chlorine shock? Do you use any dichlor or trichlor at all?