How much borax is TOO much?

[SteveMac]

We've been using the BBB method since starting up our pool on July 1st. It's 3740 gallons and to date, we've used roughly 95oz (almost 6lbs) of borax to adjust the pH. The fill water was from the town supply and it's pH was very low. Our TA is currently around 90-100 and the pH has been holding steady around 7.2. We'd like to be around 7.5, but are concerned about adding any more borax to the water. We've read that unlike chlorine, the borax will remain in the water and becomes toxic at higher concentrations. Our question is, how much is too much? Have we already used too much for a pool this size?

As for the rest of the levels, our CYA is 30-40 and we've been holding FC around 5-7. Also using 4-6oz weekly of Stain prevention and remover to keep the water clear. The BBB method combined with the apparent metal(s) in the town water likes to turn the pool a transparent green color.

 

[chiefwej]

Those that borate the pool, (including me) run at a level of about 50 ppm. That would be about 14 pounds of Twenty Mule Team Borax, given you pool volume. You would have to get much, much higher than that before getting into any toxicity problems.

 

[frogabog]

Many of us actually add borates to 50ppm for these reasons:

1) more stable pH
2) Algaestatic properties
3) reduced chlorine usage
4) silkier feeling water--less skin and eye irritation
5) clearer, 'sparkling' water
from so-you-want-to-add-borates-to-your-pool-why-and-how-t4921.html

According to the pool calculator, 96oz of 20/20 Mule Team will raise your borates by 22ppm. So, you're well away from any danger of being borated by using borax to increase pH :~}

I've got to say, the borates have served us well, into the 3rd season now. This year borates were low at opening, somewhere between 15 and 20ppm. The water lost it's sparkle and didn't get it back till borates were added back to 50+ppm. There's a significant difference in the glintiness and sparkle, after becoming used to it for a couple years it was apparent when it wasn't quite enough.

Borates in the 50ppm to 80ppm range are considered acceptable, but most of us aim for 50 and keep it there.

 

[257WbyMag]

If you are wary of using too much borax, you can consider aeration to raise your pH.

 

[supertune]

Hi SteveMac,
I would raise the TA up to 120 and see if that gets the pH up a little higher and holds there. Here is from Pool School:

You can raise TA with baking soda. It is often best to make large TA adjustments in a couple of steps, testing the water after each one, as adding baking soda will also affect the pH and you don't want the pH going out of range. If you need to lower your TA level, see How To Lower Total Alkalinity.

Chuck