First Spa, Plan of Balancing Water

[Madison Mike]

First post, be nice!

My tub should be filled shortly, as the final electrical work is being done now. Here are my test results from my well water:

Straight from the well: TA 400, pH 7.2, CH 280

Softened water from tap: TA 390, pH 7.4, CH 0

I used the Taylor K2106 kit for my testing, and I would assume these values are good, as I did them twice. I was thinking that with a high TA, shouldn't the pH be high also?? I thought they went hand in hand.

I plan on filling the tub with 1/2 to 3/4 well water, and the rest soft water. I am shooting for a CH of 150-200. After the fill, I plan to aerate first before I add any acid to bring the pH up, or should I add a small amount of acid first, and then aerate. I plan on using muriatic acid to lower the TA. I did read in my jacuzzi manual to never add acid to the tub?? Well, how do you balance your water then? hmmmmm. I will aerate for 20-30 minutes, and then recheck levels. From what I am reading, it could be a long process to get my TA down to 100 or so? Or is it easier with a hot tub and all the aeration jets?

Yes, I realize this forum is geared for pools, but the other forums I joined seem to have very little traffic. Thanks for any insight you can give me as a first time spa owner.

Mike

 

[chem geek]

Welcome to TFP! Sorry to not respond sooner.

With a high TA the pH will get high when the water is exposed to air, especially with aeration. When in the ground it won't necessarily rise in pH as much and there may be acidic soil or other sources making the water getting into the well lower in pH than expected. Your plan is sound to use a mix of water to get the CH down. 150 ppm would be a good target for CH.

You can add acid to get to a pH of 7.0 for aeration as that will drive the carbon dioxide out faster. I don't know why your jacuzzi manual says never to add acid. Perhaps they mean Muriatic Acid but dry acid is OK? Either way, so long as you add it slowly with the circulation running you should be OK. They are just worried about you pouring acid in one place that settles onto a spa surface.

I don't think it will take that long to get the TA down because a spa's aeration jets really drive the carbon dioxide out pretty quickly. It's MUCH faster than the process for a swimming pool.

 

[Madison Mike]

Thanks, chem geek. I have my TA down to 90, and pH is around 7.8 using the acid and aeration. Do I dare go down any more with acid, or would you leave it where it is? I have boric acid coming in the mail, should be here Monday or Tuesday. When I add my 50ppm of borates, I should be all set.

 

[Richard320]

Thanks, chem geek. I have my TA down to 90, and pH is around 7.8 using the acid and aeration. Do I dare go down any more with acid, or would you leave it where it is? I have boric acid coming in the mail, should be here Monday or Tuesday. When I add my 50ppm of borates, I should be all set.

http://www.troublefreepool.com/threads/4655-So-you-want-to-add-borates-to-your-pool-Why-and-How says to take TA all the way down to your target. You need to adjust the pH again anyway, so it should keep dropping.

 

[Madison Mike]

Richard, what is my target, or what dictates the correct target? I added one more once of muriatic acid, and got a pH of 7.6, TA 70. My CSI is at -0.12. If I lower my pH any more, my CSI will keep going down. I also did the acid demand test. I added two drops, and the pH read 7.2.

 

[Richard320]

Richard, what is my target, or what dictates the correct target? I added one more once of muriatic acid, and got a pH of 7.6, TA 70. My CSI is at -0.12. If I lower my pH any more, my CSI will keep going down. I also did the acid demand test. I added two drops, and the pH read 7.2.

That link I posted recommends 70 as a target. So you're there.