Higher TA and Borates

[Uncle Salty]

I see it's recommended to lower your TA prior to adding Borates but I'm wondering what the implications are if you add them with a high TA level? Here are my numbers:

FC-8
CC-0
PH-7.5
TA-170
CH-70
CYA-70
Water temp-85*
Salt-3100

This gives me a CSI of -.55 according to Pool Math, which is acceptable. So what problems will I incur if I added Borates of 50 ppm and left the TA where it's at?

Salty

 

[JoyfulNoise]

The problem with adding borates is that it acts as a pH buffer and so you will need to add about twice as much acid to get the same change in pH as you would with 0 borates. Now, the pH rise will be slowed by borates so, over time, you add about the same amount of acid. Since lowering TA requires an acid/aeration process, having 50ppm borates on board makes that process a lot slower.

Since you have a vinyl pool, a negative CSI is not really a big deal. However, I would say that in general terms you CH is too low. For vinyl it is recommended that you try to have at least 150ppm CH to reduce the chance of foaming in water and it's best if you can try to keep it up near 200ppm. That will make the CSI more positive and allow you to both lower TA and add borates without issue.

 

[AimeeH]

That might depend on what you are adding. Boric acid or 20 mule team borax? Use pool math at the bottom of the page is a feature that gives you the effects of adding specific chemicals.

- - - Updated - - -

And Matt's answer is much more complete than mine

 

[Uncle Salty]

The problem with adding borates is that it acts as a pH buffer and so you will need to add about twice as much acid to get the same change in pH as you would with 0 borates. Now, the pH rise will be slowed by borates so, over time, you add about the same amount of acid. Since lowering TA requires an acid/aeration process, having 50ppm borates on board makes that process a lot slower.

Since you have a vinyl pool, a negative CSI is not really a big deal. However, I would say that in general terms you CH is too low. For vinyl it is recommended that you try to have at least 150ppm CH to reduce the chance of foaming in water and it's best if you can try to keep it up near 200ppm. That will make the CSI more positive and allow you to both lower TA and add borates without issue.

Intersting, so you would advise upping my CH to around 200 and then go the acid/aerating process. I have a homemade aerating device I cobbled together from another thread I read on here but haven't used it yet and wondered if I just left the TA high what problems it might create. So for calcium chloride I can just use like a deicer from Lowes to raise my CH or is it okay to just order the Clorox CH up stuff? Thanks for your input.

Salty

- - - Updated - - -

That might depend on what you are adding. Boric acid or 20 mule team borax? Use pool math at the bottom of the page is a feature that gives you the effects of adding specific chemicals.

- - - Updated - - -

And Matt's answer is much more complete than mine

I'm using Boric acid, I actually have 110lbs of it as my order got messed up and I received two 55lb pales for the price of one, so I'm set for a while.

Salty

 

[JoyfulNoise]

You really need to get that TA down. Carbon dioxide outgassing is the largest source of pH rise (acid demand) in any outdoor residential pool. With 170ppm of TA, your pool water is very much over-carbonated relative to atmospheric CO2 levels. Therefore all of your acid demand is from the TA. Getting it down to 80ppm will have a huge impact on your pool's pH stability. You might not even need the borates.

As for CH sources, road deicer is typically a bad choice. Deicers are usually a cheap blend of mostly salt (sodium chloride), a minor amount of calcium and magnesium chloride, and good helping of dirt. You'd be better off using pure calcium chloride or some retail brand of CH Up.


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[Uncle Salty]

You really need to get that TA down. Carbon dioxide outgassing is the largest source of pH rise (acid demand) in any outdoor residential pool. With 170ppm of TA, your pool water is very much over-carbonated relative to atmospheric CO2 levels. Therefore all of your acid demand is from the TA. Getting it down to 80ppm will have a huge impact on your pool's pH stability. You might not even need the borates.

As for CH sources, road deicer is typically a bad choice. Deicers are usually a cheap blend of mostly salt (sodium chloride), a minor amount of calcium and magnesium chloride, and good helping of dirt. You'd be better off using pure calcium chloride or some retail brand of CH Up.


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Okay, I'll give the acid/aerating a go this weekend and thanks for your guidance.

Salty

 

[Uncle Salty]

So after 5 days of adding MA and aerating here's my new numbers:

FC 7
CC 0
PH 7.6
TA 60 added 3.5 gallons of MA, was at 170
CH 225 added 35lbs of CH up, was at 70
CYA 70
Salt 3500
Temp 86*
Borates 0

Can I safely add my boric acid at this point or do I need to let the water stabilize for a bit? Can I also add the whole 55lbs or so to get me 50 ppm in one application or do you recommend spreading it out over a couple of days?

Salty