Granubor, Solubor,

[firstladykatie]

I read through all 29 pages of the “So you want to add Borates” thread in one sitting today. I read with interest the two posts from Big Island Pool Service about Solubor vs Granubor on pp16ish. I also read the links to Richard’s posts on Borax sources and the first inquiry about about Solubor. Now my head is swimming, and I have a question. I have a free source of Granubor (from my farming brother who also gifted me the grain bin from which I built my pool). Since my pool is 34k, that means a substantial savings over the necessary amount of Boric acid, even if I still pay for the Muriatic Acid. I did see percentages in the threads that should help me calculate the amounts needed (since Pool Calculator doesn’t factor Granubor). But I can’t find them and proabably don’t trust myself completely even if I had them in front of me. Could someone verify that Granubor IS a viable addition to test drive borates in my pool this summer (label photo attached), and if so, also help me calculate the amounts I should add of the Granubor and the Muriatic Acid? Meanwhile, I am lowering the TA now because it is at 110.

 

[kimkats]

KATIE!!! HI!!!!!!!! How is your beast of a pool doing???

I am going to ping Matt (joyfulnoise) who is my go to guy for this kind of thing! Hold on a bit until he gets back with us.

Kim

 

[JamesW]

Sodium tetraborate pentahydrate is ok to use. However, do you know how pure this product is? Does it contain any harmful impurities?

It appears to be mostly pure. But, impurities, like iron etc might be an issue without knowing for sure.

Tetra borate pentahydrate is in poolmath.

 

[firstladykatie]

Kim, pool is great! Opened clear again this year, have a huge new deck (aircraft carrier sized to match pool), and had our first party Saturday to celebrate child #2’s college graduation. Next group is little ones coming over this Sunday! Weather and water are beautiful here. James, thank you. Have you read the thread on Solubor and Granubor?

 

[JamesW]

I suspect that it's probably ok. I just don't know if there are any impurities to worry about.

 

[JoyfulNoise]

All the SDS information I find says it's high purity sodium tertraborate pentahydrate. It should be fine to use. If it is very granular then it might take a while to dissolve. You're going to want to add it slowly in smallish batches and then adjust pH using muriatic acid. You should have a pool brush handy as you are going to want to brush it around as it dissolves to avoid localized scaling from high pH.

 

[firstladykatie]

Thanks. In the posts I referenced, it seemed it should only take about half as much of this as the borax. That is not what I see when I plug it into the calculator as James suggested. Ideas?

 

[JoyfulNoise]

Thanks. In the posts I referenced, it seemed it should only take about half as much of this as the borax. That is not what I see when I plug it into the calculator as James suggested. Ideas?

You should use Pool Math to do these calculations and not anything that someone may have posted in a previous thread. Pool Math calculations are used by thousands of pool owners everyday and they are spot-on accurate. When using the borax/muriatic-acid method, it is best to add the borates in small batches, maybe break up the total amount needed into five smaller batches. Because the pH rise from borax is so strong, you absolutely DON'T want to add the entire amount all at once. This is why many borate users prefer boric acid - it's a weak acid and doesn't change the pH much at all on addition so you can add the entire amount all at once.

 

[JamesW]

It's the solubor that takes about half the amount. You have granubor.

Solubor is disodium octaborate tetrahydrate. Octaborate has 8 boron atoms (octa = 8). You have tetraborate, which has 4 boron atoms (tetra = 4).

So, you get twice the boron in solubor as you get in granubor.

 

[firstladykatie]

Thanks! I found Jason Lion’s post I was remembering about it not being in PoolMath. It was the difference in Granubor and Solubor formulas I wasn’t understanding. I appreciate the help!

 

[kimkats]

Oh and where is a pic of said deck????

 

[firstladykatie]

Coming soon! Have two kids out with wisdom teeth so playing nurse this week. Have a great summer, Kim! You’re the best! And I am going for it with the borates as soon as I get my PH back up after adding acid last night to lower TA. Thanks again, Joyfulnoise and James!

 

[kimkats]

TWO??? your wallet is hurting also!!!