Questions about adding Borates

[msujohn]

I'm at the point in the very near future that I plan to add borates to the pool. But have a few questions.

- I have a 23,000 gallon pool and want to get my borates up to 50PPM. Based on calculations I should add 18 boxes of borax and 5 gallons of MA. I didn't screw up the calculations did I? I know I will add 1/2 at a time like mentioned in instructions.

- My first thing I need to get under control is to make sure my TA is about 60 or 70 correct? it's currently at 90 and I'm working to reduce it by the aeration method. Here is my question: I have quite a bit of areation in the pool on a regular basis (SWCG, Spa spill over, and large waterfall). Do I run the risk of getting my TA to low over time since this is a new pool (I'll be adding alot of MA) and the areation will bring it up frequently? Is it important for me to initially get my TA to 60 or 70 prior to adding borates?

- How long do I need to keep the kids out of the pool after I add the borates?

 

[maxepr1]

Getting your TA down first will be easier BEFORE you borate. I would let it dissolve for an hour or so before swimming, it's not going to hurt anytime sooner. 18 sound about right. msujohn my pool is like a roller coaster with my TA and PH all summer long. But Borating will stabilize the PH more.

 

[257WbyMag]

Agree with maxepr1. Adjusting TA after adding borates is very difficult. Get the TA where you want it first and then add the borates.

Whenever the borates are dissolved, pH is adjusted, and everything looks good, swimming can commence.

 

[Red Shirt Ensign]

Why is it important (again) to reduce the TA? As long as you add the MA and Borax... shouldn't it just work? I did it last year according to instruction but I didn't really understand why it was so important... the borates definitely improved the feel of the water though and its totally worth doing in my opinion. Before we added, using liquid chlorine, seemed to make the skin very dry, this was totally changed by the borates!

Definitely worth doing

 

[ping]

How old is your pool? I added borates to my pool when it was about 6 months old and I will say that it didn't make much difference to my pool. I already had the SWG like you do, so I had a "softer feel" to begin with. One thing that I did notice is that it required more acid at a time when adjusting the pH, but it went from every 5 days of adding acid to 7 days. The overall amount of acid that I was using remained the same each month.

Personally I wished I did not add borates to my pool at that time. I was hoping for a longer time between acid additions than what I got and for the feel of the water. No one said they noticed a change in my water after I added borates.

 

[chem geek]

Why is it important (again) to reduce the TA? As long as you add the MA and Borax... shouldn't it just work?

Because the borates buffer the pH of the water, it takes more acid to lower the pH to the 7.0-7.2 range where carbon dioxide outgasses faster. On the plus side, the pH will stay lower longer so you won't have to add acid as frequently to keep it low during the TA lowering process, but you'll also have less frequent an indication of your progress as a result (unless you test the TA). Then, when you want to raise the pH back to the normal range with aeration, it takes more carbon dioxide outgassing to do so due to the borates pH buffering.

So while the TA lowering procedure still works when you have 50 ppm Borates, it can be a more frustrating or at least confusing process due to the less rapid feedback of what is going on when using pH as an indicator.

 

[chem geek]

How old is your pool? I added borates to my pool when it was about 6 months old and I will say that it didn't make much difference to my pool. I already had the SWG like you do, so I had a "softer feel" to begin with. One thing that I did notice is that it required more acid at a time when adjusting the pH, but it went from every 5 days of adding acid to 7 days. The overall amount of acid that I was using remained the same each month.

For some pools, the algicidal properties of the Borates reduce some nascent algae growth so lower chlorine consumption, though a proper FC/CYA level would normally handle that. Your pool may be lower in algae nutrients or you are more diligent in maintaining an appropriate FC/CYA level so didn't see this extra side benefit.

And yes, borates don't normally reduce the amount of acid you add -- just how frequently you need to add it. It is the setting of a higher CYA level to reduce chlorine loss from sunlight and the setting of a lower TA level and higher pH target to reduce carbon dioxide outgassing that lower the amount of acid needed to control pH.

Usually, 50 ppm Borates would cut down the rate of pH rise (above pH 7.5) by about half. However, the borates become a much stronger pH buffer at higher pH so if one targets a pH of 7.5 instead of 7.7 or 7.8 then you will not see as much benefit.

Anyway, your experience is one reason why they are considered optional. They help some pools more than others. About the only time they are pretty much required is in a spa using the Dichlor-then-bleach method if aeration jets are used when soaking because in that case there is so much aeration that additional pH buffering is nearly always required.