Lower TA, then raise PH, then lower TA....?

[jasolution]

I'm a new spa owner and am struggling with what appears to be a common problem due to lack of experience and knowledge about water maintenance chemicals.

Out of the tap, my water has TA of approximately 300 and PH of 7.4 (well water, SE Michigan). In order to bring the TA down, I use nearly 3/4 of a bottle of LeisureTime Spa Down (granular). By the time I get the TA down to 150, I've also lowered my PH to about 6.6 or so.

I've read the Sodium Carbonate vs. Sodium Bicarbonate postings, and both sound like they will raise PH, while also brining TA up too. What I've been unable to determine is whether there is a product that will increase PH without significantly raising TA too? Or is there a product that will lower just TA without lowering PH?

For those who are wiser than I about such matters, can you offer some guidance on balancing TA and PH when the two are opposite one another?

Thank you!

Jason

[windsurfdog]

Sodium carbonate (soda ash) will raise pH without affecting TA.  Sodium bicarbonate (baking soda) will raise both.  Your approach sounds correct if you will then use sodium carbonate to raise the pH.

[bulmer4nc]

What can you use to lower PH and not TA?   Our TA started off around 40 and I had to raise it but our PH was high and when I lower with SPA DOWN it lowers TA as well.  I don't want to have to SPA DOWN to lower PH and then add the Alk Increaser to put the TA back up.

[Spa_Tech]

windsurfdog is right on the money in the solution to this apparent water chemistry paradox.

But Id just point out that using 3/4 of a bottle of Sodium Bisulfate is overkill.

Leisure Time's Spa Down instructs to use 1 1/2 tsp to the spa water if the pH remains high. It doesnt give specifics about TA, however since we are talking about acid its best not only to use the amounts recommended by the manufacturer, but to dilute the granulated product in water before adding it to your spa. It is better to make small incremental changes than big ones and have to recorrect later.

Of the two it is better to set and manage TA first- pH typically 'travels' with Total Alkalinity- And in my opinion, its better to not be overly concerned with higher pH, as you use the spa, your body oils will naturally bring it down closer to neutral.

As new spa owners, you should expect about a 2 to 3 month learning curve, before youre tuned into what your spa needs.

[jasolution]

Spa Tech, you make a good point about 3/4 of a bottle being overkill...that's what I thought as I kept adding it, but was not seeing any results. I used about 3/4 of a bottle over the course of a week to finally get TA down in the 150 range. My TA test kit stops at 300, so I am not sure how high my TA really is.

After two days of adding Spa Down every 60 minutes with no noticable change, I went out and bought a different type of test kit to make sure that my test kit was working. The new test indicated that the TA was still "off the charts."

It took me a week of continually adding Spa Down to finally get the TA into an acceptable range, my guess is that I used 1/2 to 3/4 of the bottle, depending how full it was when I bought it.

I had to drain the spa yesterday because I had to move it to perform a repair on my deck, and this time the dealer recommended using a mix of 25% to 50% of soft water from inside the house with "normal" water from the outside spicket that bypasses the softener.

Thus far, the softened water appears to have the same high TA measurement as the non-softened water, so I'm not sure that this is going to make it any easier to lower my TA.

As of this afternoon, I've used 20 teaspoons of spa down, and still have a heading above 300 on my TA. I've been adding the Spa Down in two teaspoon increments, waiting an hour, then testing.

Is there perhaps a more effective product to lower TA than Spa Down?

Thanks,

Jason

P.S. My spa capacity is 500 gallons

[Shut_Down_Stranger]

ok....

your well water probably has high hardness as well. hardness is calcium and magnesium plus carbonate (CaCO3 or MgO3).

that is not uncommon for well waters, if you water is from a limestone formation, it will have passed through calcium carbonate. CaCO3, hence your high alkalinity.

Alkinlinity is the amount of acid (in mg/L) required to lower the pH to a value of 4.0.  That is really all it is.

if your well water has high carbonate, there is probably not much you can do. Increasing you pH will increase your carbonate as well as the bicarbonate is is equalibrium with bacarbonate/carbonate as a function of pH.

Lowering you pH will reduce your alkilinity, but it will probably be high. As you indicated 6.6 just lowered it to 150, so the water has high bicarbonate/carbonate.

Carbonate will raise the pH faster because the hydrogen ion is missing. The difference between bicarbonate (HCO3-) and carbonate (CO3--).

Personally, I would not worry too much about the TA and focus on keeping the pH between 7.2 and 7.6. This is more important as the slightly alkaline condition will reduce the wear on pipe and other components of the spa.

the only other alternatives are 1) to fill the spa from a non-well water source 2) fill your spa using one of those car deionizers that promise a spot free shine, the deionoizers will remove most of the mineral content in the water (calcium and carbonate).

You can also find deionizer from a place like cole palmer.    

If you remain on well water consider using more of a mineral guard because of the likely high hardness of you well water.

I do not know of anything that will remove the carbonate from the water.