high pH chemistry

[psanta33@gmail.com]

I have read your article on high pH pool chemistry and would like to try it. I am currently increasing my pool pH using Borax and will then need to raise the Total Alkalinity (which is currently at 50ppm). Calcium hardness is at 100ppm. pH is closing in on 7.8. I understand that after the pH is adjusted, I can then target the TA. I intend to use Baking Soda for this (is that OK)?
Also, I am interest in the special super chlorination method you mentioned in the article. My pool is a salt water pool and doesn't seem to need regular super chlorination (combined chlorine reading remains near 0). I don't think I did it more than a few time last season. Should I super chlorinate with the chlorine generator, or is calcium hypochlorite better? Is weekly a must?

[PoolDoc]

Don't do that!

The point of that article (now almost 15 years old!) is that a lot of the pool chemical rules aren't nearly as absolute as the guides suggest. Deliberately running at high pH is not of value to most people. The only value is, that for some people, there's no point to fighting their pH as much as they do. And, you do NOT want to use cal hypo on that way with an SWCG; you'll tend to foul your plates with calcium.

It really sounds like you may be trying to fix something that's not broken. If your pool is working well, and your numbers are acceptable, why change?

[waterbear]

You might be better served by making some water balance adjustments that tend to make a salt pool a bit more stable in terms of water balance. The main problem with salt pools is rising pH (because of the outgassing of CO2 from the aeration of the water while the cell is on is the primary cause of pH rise in salt pools.). and there are a few things you can do to minimize this.
1. Keep your CYA at the recommened MAXIMUM (usually 80 to 100 ppm, depending on manufacturer). This will translate into less cell 'on' time and therefore less outgassing of CO2.
2. Run your FC at a MINIMUM of 5% of the CYA. This will, in the vast majority of pools, insure that you won't have problems with chloramines or algae. An exampe, if your CYA is 80 ppm you do not want to EVER let the FC drop below 4 ppm. IF and when you ever need to shock the pool use liqiud chlorine or bleach and shock to about 5 times the minimum FC level.
3. Keep TA (bicarbonate in the water) on the low side (70 ppm is a good place) because the lower the TA the slower the outgassing of CO2. The explanation is rather technical and I did explain it once in The China Shop (http://www.poolforum.com/pf2/showthread.php?7570-Carbonate-Alkalinity-(adjusting-TA)&p=49434#post49434) section of the forum. (If you have a plaster pool you might need to increase your calcium hardness to maintain water balance if you lower the TA by a significant amount.)
4. Don't lower the pH below 7.6 since the lower you put the pH the faster CO2 will outgas (because the lower the pH the more you convert bicarbonate in the water into carbonic acid which is basically just CO2 dissolved in the water and the more CO2 in the water the faster it will outgas).
5. Don't worry about lowering the pH until it climbs ABOVE 7.8. You should be monitoring pH on a regular basis so this should not be an issue. Once you 'get to know your pool" you will quickly learn that you need to add X amount of acid every Y days to maintain the pH in the desired range so it is not as difficult as it sounds!
6. Consider adding 50 ppm borate, it adds a secondary pH buffer that works together with the bicarbonate buffer to help maintain the pH in the neighoborhood of 7.7 to 7.8 for an extended period of time compared to without borate in the water. You can add borate with a commercial borate product for pools (expensive) and muriatic acid (some of them are pH neutral and don't need the acid but are even more expensive) or with borax and muriatic acid or boric acid (more expensive).

[Watermom]

Evan,
That was a very good and helpful post. After I move this post into the SWCG section of the forum where it should be, I'm going to sticky your post. I think it will be helpful for SWCG owners to read.

[waterbear]

thanks, I am getting tired of typing it over and over again!:p

[Watermom]

Oh, yeah. I know what you mean!