Should liquid chemicals be diluted before adding to the pool?

[three4rd]

Hi,

I recently discovered that I have been inadvertently acid washing my new quartz plaster surface by adding dry acid to keep the pH down. I noticed this by seeing that there are a few areas that are a bit darker than the rest of the pool - so I must be wearing away the cream and exposing the aggregates in those places where I typically broadcast the dry acid even though it certainly appears to basically dissolve on contact with the water. I realize this process of exposing the quartz crystals will occur natually over time, but I'd rather not hasten the process. I would rather the plaster age more uniformly in appearance. So from now on I will dilute the dry acid first. That being said, is it necessary to also dilute liquid chemicals? My sanitizer, algaecide, and oxidizer are all liquids. Will adding these contribute to exposing more quartz?


Thanks.

 

[Smykowski]

All liquid chemicals can be poured slowly (pencil size stream) in front of the return stream with the pump running. They will mix nearly instantly.

 

[three4rd]

Is pouring in front of the return lines better than adding a small amount of liquid at different areas of the pool, which is what I've always done when adding a quart or two of oxidizer.

 

[jblizzle]

Yes, because it mixes the chemicals quickly. If you spread it around it might end up in an area of low circulation.

 

[three4rd]

My main concern is to not continue to unintentionally acid wash more of the quartz. My pool plasterer is recommending to dilute everything just to be on the safe side. So probably diluting PLUS pouring near the returns would be the safest way. Wouldn't it only be acid that would contribute to eroding the cream surface of the plaster?

 

[jblizzle]

Likely acid would be the only concern ... although it is also the chemical that I want to handle the least and thus do not want to be fooling around with the noxious fumes while trying to mix it into water and then carry a bucket around ... more chances of spilling.

 

[JVTrain]

I understand that you'd be cautious with new plaster but it is really safe to pour slowly in front of a return with the pump running during and for at least 30 minutes after adding. If you want to be even more cautious, you can add it in front of one return for a short time, then move to another, etc. Diluting acid can be risky in itself, to you. You could also buy the 10 baume instead of the 20 so you wouldn't have to manually dilute. The fumes generated during the opening and addition of acid (and more so with diluting) are more of a concern than any damage to plaster when used correctly.

Low CSI levels (determined by CH, TA, CYA, Salt, Borates and pH) are the threat to being corrosive to plaster, not the addition of acid itself. Low negative CSI is most strongly affected by low total pool pH.

 

[three4rd]

Hi,

Thanks for all the advice. The acid dilution is not an issue since I'm using dry acid, not MA. I've been keeping an eye on the SI, having just fully learned about how to use this since coming here Prior to that, I always saw it on the pool store test result printouts, but never really bothered to research what it meant. My SI has been generally staying between 0.2 to 0.

 

[chem geek]

In addition to slowly pouring over a return flow, you should lightly brush the area where you add the chemical to ensure thorough mixing. Some chemicals are heavier than water until fully dissolved so if they settle to the bottom where there is little circulation then the pH can remain low there long enough to bleach out color in colored plaster.

 

[three4rd]

Great advice chem geek...thanks!