Original > Hot Tub Forum
Lowering TA
Nitro:
--- Quote ---I am confused. How is TA of 50 excellent?
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Because his pH is 7.5, AND the fact he just lowered his TA from over 400 ppm to 50 in a day. Before it was taking him weeks. I'd say that is excellent. Wouldn't you?
Nitro:
--- Quote ---Checked this morning and ph was 7.5. Alls well. This was the easest I have ever balanced water. Took over 4 cups of acid but never got ph to low to hurt anything. Think I am going to go ahead and try Silken which will raise my ph again but should get it right back in again.
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I'm not familiar with all the ingredients in Silken, so use it at your own risk. I don't think it's pH balanced, so you may need to add Acid to counteract it. For the price, you'd think they would make it pH balanced. Just keep an eye on your pH, and let us know how it works out.
FYI, the cheapest way to add Borates is to use 20 Mule Team (Borax) and Acid. The easiest way is to use a product called Gentle Spa, which is pH Balanced.
chem geek:
--- Quote ---I am confused. How is TA of 50 excellent?
--- End quote ---
Assuming your question is about how a low TA is good, you need to remember that the primary SOURCE of rising pH is carbonates (in particular, dissolved carbon dioxide) in the water and that is measured by TA. If you are going to use a net pH neutral source of chlorine, such as bleach or lithium hypochlorite, then you want the TA to be fairly low to minimize the pH rise. If, on the other hand, you use a net acidic source of chlorine such as Dichlor, then you want the TA higher to balance this acidity to keep the pH fairly constant or only slightly decreasing (though the TA will slowly drop over time requiring baking soda to bring it back up).
This is similar to pools where the standard recommendation is 80-100 ppm for hypochlorite sources of chlorine and 100-120 ppm for other sources of chlorine including Trichlor and Dichlor. Spas have a lot more aeration than pools and are at hotter temperatures so the rate of outgassing is quite a bit faster, so an even lower TA for hypochlorite sources of chlorine is desired. If one wants more pH buffering, then one can add 50 ppm Borates to the water since that is a pH buffer that does not cause a rise in pH over time.
Richard
brian_tr:
I like to get my chemicals from local dealer when possible. Silken (Sodium Teraborate Petahydrate 100% ) is the only thing that came up on search for Spa Guard Chemicals that said borates is why I thought about trying it but maybe I will just order Gental Spa on line.
chem geek:
--- Quote ---I like to get my chemicals from local dealer when possible. Silken (Sodium Teraborate Petahydrate 100% ) is the only thing that came up on search for Spa Guard Chemicals that said borates is why I thought about trying it but maybe I will just order Gental Spa on line.
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As you point out, SpaGuard Silken, according to the MSDS, is 100% Sodium Tetraborate Pentahydrate. This will not just add borates to the water, but will raise the pH significantly as well. You would need to add acid along with this product so if you were going to do that then you could just as well use 20 Mule Team Borax (Sodium Tetraborate Decahydrate) though the Silken product is pretty darn cheap. You can see from the instructions here that they say it will raise the pH and that you will need to add acid. Their dosage for the acid is incorrect. If they are using volumes, then the 10 ounces volume of their product would need 6.4 ounces volume of dry acid, not 5 -- perhaps their product density is very different than normal. The dosage amount they give adds around 65 ppm Borates.
With the ProTeam Gentle Spa, this is pH neutral so no acid is needed. The dosage they give adds around 35 ppm Borates so you can scale this up somewhat to get to 50 ppm.
Richard
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