I really feel stupid for asking, but how does 12 oz. of borax raise 1000 gal water 10 ppm? I've tried to do the calculation for about a half hour. I keep getting 100 ppm. 12 oz. = 339.6 g or 339, 600 mg. 1000 gal = 3800 L = 3800 kg. The calculation for ppm as I understand it is milligram solute/kilogram solvent, so 339,600/3800 = 89.37 ppm. Did I miss something? The only reason I ask is because I want to see how much the salt level is risen after you add borates (and because I'm a chemistry nerd).

Borates are measured in units of parts-per-million (ppm) or milligrams-per-liter (mg/L) Boron which has a molecular weight of 10.8117 g/mole. You should not be using the weight of 20 Mule Team Borax product directly which is Sodium Tetraborate Decahydrate with a molecular weight of 381.37 g/mole which will give you a result that is 381.37/(4*10.812) = 8.818 too high. Also note that tetraborate has 4 boron which is where the "4" in my calculation comes from.

12 ounces of Borax raises the Borates level by 10.19 ppm in 1,000 gallons. 12 ounces is 340194 mg and 1000 gallons is 3785.4 liters. (340194/3785.4)/8.818 = 10.19.

The ppm units can get confusing. All chlorine is measured in ppm Cl₂ while Calcium Hardness (CH) is measured in ppm CaCO₃ and the most confusing is Total Alkalinity (TA) that is also measured in ppm CaCO₃ but based on carbonate being able to take up two hydrogen ions so when converting TA into a sodium bicarbonate equivalent one not only has the molecular weight conversion, but a factor of 2 since bicarbonate can only take one hydrogen ion.

So that's like saying there's 11% boron in sodium tetraborate hence there's 37421.34 mg in 12 oz. of borax.

I must say chem geek, you are a rock star, I majored in chemistry so I love whenever you blog. But really, you just took hours of calculation and research and condensed into three paragraphs.

hats off

Yup, that's correct, though it's more accurately 340194 * 4 * 10.8117 / 381.37 = 38577.5 mg in 12 oz. of borax where there's 11.34% boron in sodium tetraborate decahydrate.

kellyj, thanks for the compliment. When I first started doing pool water chemistry calculations years ago, I wasn't sure of the chlorine units and incorrectly used the molecular weight of hypochlorous acid instead of chlorine gas. It was almost a year before I confirmed the proper units and had to redo the charts and graphs that I had made. Such a simple thing, but not always easy to find.

This is a great post (thanks for posting waterbear!). I have just learned a lot more about borates. But I have a quick question. Instead of using the Muriatic Acid to reduce the pH, could I also use one of the commercial pH Down products? I ask this because my PB left me with quite a few bottles of pH Down when they started up the pool, which I never used. They were expecting a HUGE spike in the pH level and it just never really came. So I've got 3 big bottles of the pH Down stuff sitting on the shelf already. Is there any difference between using this versus muriatic acid?

Yes, you can use PH Down, though we don't normally recommend it because of the added expense.

It is worth noting that muriatic acid can cause burns quite easily. I was bringing 4 gallons home in my car. They were on the floor in plastic bags. I was in a hurry and drove frantically (big mistake). I made sure the bottles were all sealed properly before buying them in case they tip over in the car, which of course they did. I thought no big deal, intil I went to get them out. One of the bottles leaked a little and burned a hole about the size a half-dollar into my floor mat. Luckily, it's in an inconspicuous spot. Lesson: When transfering muriatic acid, use a plastic bin.

I'm interested but when I calculate the cost of 12 boxes of borax and 4 gal of MA I come up with about 90 bucks. If my calculations are correct for Proteam supreme plus it would cost about $100. I'm making a mistake? It seems it might be easier to buy just one product.

After double checking prices it looks like it would cost me $140 for Supreme plus.

macgasת
I think it is worth to trust the big guys/experts of this forum. They did the math and it is cheaper to buy the borax and the MA...

Ignoring cost, is it better to use boric acid or borax + muriatic acid? I guess what I'm curious about is does the reaction between the borax and muriatic acid to lower the pH add other chemicals to the pool water?

It is a price and convience issue, the end result is the same.

Using Borax + Muriatic Acid will increase the salt level in the pool whereas using boric acid will not (I'm talking about "sodium chloride" when I am referring to salt). Adding 50 ppm Borates using Borax + Muriatic Acid increases the salt (sodium chloride) level by around 125 ppm. Nothing to worry about, of course.

It may have already been mentioned in this thead, but at 10 pages now, I'm being a little lazy. My question is, can you have TOO much/many Borates like you can with Cyanuric Acid...read as, does having too much/many Borates cause any problem like having too much CYA counteracts chlorine effectiveness?

We recommend borates between 30 and 50. Borates up to 80 is fine. Borate levels above 80 are discouraged for a couple of relatively minor reasons, nothing goes wildly wrong right at 81 or anything. As borates get higher one of the issues will be environmental effects. You don't want to release any more boron into the environment than you have to.

Don't know if this was ever answered. Can I do this over a period of time?

You can certainly add the borates piecemeal since it doesn't go away except from dilution. The risk of the lower borate levels is that it's a nutrient at such low levels, though not usually as limiting as phosphates and nitrates. However, if one is maintaining a proper FC relative to their CYA level, then this shouldn't matter. Somwhere around 30-50 ppm, the algaecidal levels of borates kick in for many algae and slow down their growth. Bottom line, I wouldn't worry about it -- you can add it slowly over time if that's what you want to do.

Hello All, and Thank You again for these forums and good information.
I followed to the T, the How instructions to prepare to add Borax.
Had my Total Alkalinity to 80ppm, and pH between 7.2 and 7.5. And yes these are the toughest parts to achieve in the process. Somewhere else in this site, I read that to raise pH WITHOUT raising Total Alkalinity a person uses lots and lots of tiny bubbles in the pool, who knew? Well, all of you, except me.

Still following the exact instructions, I took a deep breath - the worst is over, and added Muriatic Acid and Borax in the proper amounts and sequence and lots of brushing in between. The whole pool area smelled of fresh laundry, so cool.

The instructions say that adding the Borax will raise the Total Alkalinity and pH, hence the Muriatic Acid along with Borax, but in my case the TA went to 160ppm, and the pH must be above 8.2, my test kit only goes up to 8.2 and the results are RED, not light purple. I am slowly adding acid and will test periodically. And posting my results so others will be aware that more acid than recommended may be necessary.

Sure you were using 31.45% 20 Baume Acid and not the weaker stuff? The chemistry side is usually pretty consistent.