High PH, Low Alkalinity?

[Neo Seeker]

Hi there, first post.

I have a 3 month old pool, I've been adding muratic acid per my pool companies direction to help bring my PH down. Last time I checked it was about 7.9. I had water tested today and they told me it was High PH, 8.2 but low alkalinity. I thought if the water PH was high, this ment I had high alkalinity (hence the addition of acid)? So they sold me a product called Alkalinity Up to raise the alkalinity of the water. Will this raise the PH even higher? I'm looking for a simple explanation about this relationship or a good link! Thanks!

-Dave

 

[duraleigh]

Hi, Dave,

Welcome to the forum :lol: I am not good at the precise science but I can tell you how they apply to pools.

The good news is you can control them independently of each other.

So if your pH is too high (anything above 8.0), you can raise TA by adding just what you added (it's actually baking soda) and it will have little, if any, affect on your pH.

Pool School gives more explanations of how to move them each up and down and the acceptable ranges......that's the place I would go next

 

[PoolGuyNJ]

Acid will use the alk mostly before the pH drops. Keep adding acid.

Scott

 

[Neo Seeker]

Thanks guys! Looking for a good explanation. Any links appreciated!

 

[chem geek]

The simple rule is that if the pH is rising over time, your TA may be too high. If your pH tends to drop over time, then your TA is possibly too low.

Now there are some exceptions such as when you've got new plaster curing, then the pH will rise even if your TA is low and if you are using Trichlor tabs then even a high TA might still have the pH dropping somewhat over time, but the above rule is at least a good starting point. The basic reasoning for the rule is that TA is a SOURCE of rising pH in its own right. TA is mostly a measure of the over-carbonation of the water where higher TA means more carbon dioxide outgassing and that causes the pH to rise.

So the pool store was probably wrong telling you your TA was too low because if it was low then your pH would probably not be rising (unless you've got new plaster). Best thing to do is for you to get your own test kit, the TFTestkits TF-100 is a good choice, and then follow the advice in the Pool School and ask any questions you have here on the forum.