Borax, High Calcium, SWGs

Jump to latest Follow Reply
pcmacd

pcmacd

Well-known member
Oct 3, 2010
125
Maricopa County, AZ
My make up water comes from a well that is full of magnesium and calcium.

I live in Greater Phoenix, so the summertime make up water is LOTS.

After four years the water had so many minerals in it that I could not run the SWG for a week at a pH of 7.2 w/o fouling it!

I have just refilled the pool with City of Mesa tap water, by truck, for $550 / 18.2K gallons.

TA: 80
CH: 250

I read the following here:
"If however a user struggles to stay within our guidelines due to their fill water being high in calcium a user should consider using Borates in their water as well as attempt to keep their pH levels low. "​

I've had chemistry aplenty over the years, and I just don't understand how adding minerals to my pool might help in keeping my SWG clear of calcium AND SUCH when the replacement water starts to raise the calcium/magnesium levels. <<<-- that is my question!
  • I KNOW the water is full of magnesium, because one will be ***TING thru a keyhole if one drinks the unsoftened well water for a week or so?
  • Ask me how I know? :-[
    Water tastes great. Grrrrrrrr. Have some more?

I understand what a buffer is, though I flunked that Chem 102 test at Purdue (I was correct in assessing that i would never see those equations again in my entire mechanical engineering career? Chemistry was a freshman "flunk out course" to weed out people that might night have the guts for engineering courses to follow.)

I've been farting around here for over 90 minutes, and while it is interesting, I still have not found an answer to my question.

If somebody can give a definitive answer?
  • Let's make it sticky?
tanks
 
Ok, sorry.

Borates can help control pH rise, especially in the cell.

Try to keep the CSI between -0.3 and 0.0.

Keep the TA as low as possible.

Try to keep the pH about 7.8.

You can manage without a water softener, but you would be well advised to use one.

You can get a separate one for the pool if you want.

Either way, it's your choice.
 
  • Like
Reactions: JoyfulNoise
JamesW said:
Ok, sorry.

Borates can help control pH rise, especially in the cell.

Try to keep the CSI between -0.3 and 0.0.

Keep the TA as low as possible.

Try to keep the pH about 7.8.

You can manage without a water softener, but you would be well advised to use one.

You can get a separate one for the pool if you want.

Either way, it's your choice.
Click to expand...
Whoa!~

pH above 7.8? That is contrary to all of the advice I have gotten here for high calcium water.

In fact, I have been encouraged to keep the pH around 7.2/7.3?

You sure about that? If so, please explain, as I am now freaking bewildered?

Further, wont a pH that high tend to cause itchy skin?

tanks

mac
 
The pKa of the boric acid/borate buffer system is about 9.0 (depends on ionic strength). Therefore borates will have their maximum buffer capacity ( defined as -dCa/d(pH) or the resistance to change in pH with the infinitesimal addition of an acid or base) at a pH of 9. Inside the salt water chlorine cell, the pH can easily go over 10 near the anode and those cause mineral scaling. Adding borates cuts that pH rise down and reduces the tendency for scale formation.

Not magic, just chemistry.
 
JoyfulNoise said:
The pKa of the boric acid/borate buffer system is about 9.0 (depends on ionic strength). Therefore borates will have their maximum buffer capacity ( defined as -dCa/d(pH) or the resistance to change in pH with the infinitesimal addition of an acid or base) at a pH of 9. Inside the salt water chlorine cell, the pH can easily go over 10 near the anode and those cause mineral scaling. Adding borates cuts that pH rise down and reduces the tendency for scale formation.

Not magic, just chemistry.
Click to expand...
Thanks.

I hesitate to add any kind of mineral to my pool due to the mineral content of my well make up water, as I have trouble with my SWG fouling. It's low humidity and 110F here in the summer - greater Phoenix, so I get lots of make up water. The local river's name is Rio Salado (Salt River.)

So, add borax or not?

Will it help with the SWG fouling, which I assume is calcium (it is white?)

When the mineral content is sufficiently high, the system will actually blow chunks of minerals out the SWG before it completely fouls and stops making chlorine.

I have to put about a gallon of 31% HCL per week to keep the pH between 7.2 and 7.8. Others here have recommended keeping the pH in the low end of that range to help the SWG not foul when the mineral content gets higher.

CYA 80
FC 6, CC 1.5, TC 7.5
pH around 7.5 currently
TA 80
CH 250 (up from tanked in Mesa water at CH 201 ten days earlier.)
Salt 3100
 

Enjoying this content?

Support TFP with a donation.

Give Support
Most borate compounds are highly water soluble and will not scale out of solution. The scale you are seeing is calcium scale (calcium carbonate primarily). Calcium carbonates, phosphates and silicates have very poor water solubility and, once they form, they immediately scale out of solution. Borates reduce the pH rise inside the salt cell and help to eliminate scaling. I have used borates for the entire life of my pool and, while I do get occasional snowflakes from my returns due to high CH pool water, my SWG cell has never needed to be cleaned.

Your fill water is really no different than most areas in southern AZ. My fill water has a TA of 110ppm on average and CH of around 180ppm to 220ppm depending on the time of the year. Phoenix and Tucson get their water mainly from local wells and CAP water (Colorado river). The best thing I ever did for my pool was to add a whole-house water softener and run a line to my autofill. It was not easy and required some holes through my garage wall as well as some trenching to reach the autofill line, but it was well worth stopping the CH rise of my pool water. As I partially drain and refill in the fall months, my CH is slowly coming down. Summers are not the time to drain so I will probably exchange and couple of thousand gallons of pool water with unsoftened water out of my spigot. The softened fill line water simply keeps my CH from rising during the high evaporation months.
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply