Ph changing weekly

[Jostudly]

I would like to know how common people's ph changes on a weekly basis. I find that mine goes up every few days even know I am testing the water weekly and checking test strips daily. Use the tub 2-3 times a week for 1 hr and have enough bromine in floater. Is there a way to get ph stable so I do not need to adjust weekly?

[chem geek]

The spa water is over-carbonated (TA is a rough measure of that) so unless you are adding net acidic chemicals to the water, the pH will tend to rise, most especially if you are running spa jets that aerate the water.  Higher TA, lower pH, and more aeration all increase the rate of carbon dioxide outgassing from the spa and that has the pH rise (with no change in TA -- the TA drops when you add acid to lower the pH).

You can lessen the amount of pH rise by having a lower TA target, as low as 50 ppm if you need to.  To supplement pH buffering, you can then add 50 ppm Borates (usually using boric acid).  Also, you would maintain a higher pH target of say 7.8 and not try and lower the pH below 7.5.

[Jostudly]

I didn't think running the jets and the air would increase the ph especially when a tub is designed to use air and jets. I don't like sitting in a tub without using these features. I guess I will have to add more acid weekly as my only option. My ph decreaser is bioguard lo and slo.

[Tman122]

I didn't think running the jets and the air would increase the ph especially when a tub is designed to use air and jets. I don't like sitting in a tub without using these features. I guess I will have to add more acid weekly as my only option. My ph decreaser is bioguard lo and slo.

If your confident about having and using liquid acid it can be had in gallon jugs very inexpensively by using Muratic acid. Commonly used for cleaning concrete, and other stuff. Always dilute with water. Use a clean 5 gallon bucket and scoop out a bucket 1/2 full of tub water and pour your acid in there to mix and pour back in. Leave the jets off, pour it back in away from the edge. Don't buy scented or colored. For those of you acid crazy, Muratic acid is also in our stomachs. Some people say try lemon juice but I just keep thinking of fish sticks then

Be careful, while spilling some on your hands won't instantly burn a hole in your flesh. If you have a cut or sore it will burn like hell. Wear rubber gloves and don't spill any on anything unless you rinse it super quickly with lots of water.

[Quickbeam]

I didn't think running the jets and the air would increase the ph especially when a tub is designed to use air and jets. I don't like sitting in a tub without using these features. I guess I will have to add more acid weekly as my only option. My ph decreaser is bioguard lo and slo.

You do not need to add more acid weekly. You need to do it once and it should be O.K., although you may still get a small amount of PH drift. Look at reply #26 in this thread (http://www.whatsthebest-hottub.com/forum/index.php/topic,19197.15.html). I have laid out how to adjust your TA so your PH does not spike with aeration. The only thing I didn't include, which ChemGeek has mentioned in his reply in this thread, is to add 50 ppm Borates when you are done with the process. To find out how to attain the 50 ppm Borates, you can use the Pool Math calculator, which you can find here: http://www.troublefreepool.com/calc.html

[chem geek]

I didn't think running the jets and the air would increase the ph especially when a tub is designed to use air and jets. I don't like sitting in a tub without using these features. I guess I will have to add more acid weekly as my only option. My ph decreaser is bioguard lo and slo.

It has nothing to do with tub design.  It has to do with the fact that the water you put into the tub is over-carbonated and aeration causes this excess carbon dioxide to outgas and that causes the pH to rise.  I was not suggesting you not to use these features.  I was just explaining what happens and ways you could handle it.

When people use a lot of net acidic chemicals, including Dichlor or non-chlorine shock (MPS), then this may be enough to balance the outgassing and have the pH be more stable.  However, when using bleach or when using bromine tabs (usually with an ozonator), you aren't adding net acidic chemicals so the pH rise from outgassing is much more noticeable.

The Total Alkalinity (TA) is a measure of the over-carbonation of the water.  Generally speaking, if the pH tends to rise in water, then one needs to lower the TA level and vice versa.  This is why the suggestion is to lower the TA level and for supplemental pH buffering to use borates because they buffer the pH without any outgassing side effects.  Some people use phosphate buffers for pH, but those have other side effects precipitating calcium out of the water.