spring start up, general questions, BBB method

[chem geek]

CrisL is mostly correct, but I wanted to quantify some things. Technically, Borax or any base that raises pH will also raise the TA a little (just as any acid that lowers pH will also lower the TA a little), but it is true that it will not add carbonates to the pool and therefore will not raise the TA as much as pH Up (sodium carbonate / soda ash / washing soda). 1 pound of sodium carbonate in 10,000 gallons with your pH of 7.2 and TA of 80 will raise the pH to 7.48 and the TA to 91.3 while 1 pound of Borax will raise the pH to 7.33 and the TA to 83.1. For an equivalent rise in pH to 7.48, it takes 31.7 ounces (almost 2 pounds) of 20 Mule Team Borax and the TA will rise to 86.2, again per 10,000 gallons. So for the same pH rise it takes twice as much Borax by weight as sodium carbonate and the TA rises about half as much.

The reason for this is that Total Alkalinity includes the "alkalinity" from the difference of hydroxyl ions to hydrogen ions and this relationship is directly related to the pH. In some sense, the dissociated products of water itself act as a (very weak) pH buffer. The effect is small, but actually measurable in the TA test for larger changes in pH.

Richard

[darenjones]

first off, thank you all for the replies...
I just want to make sure that I am doing all I can to ensure crystal clear water throughout the season.
I saw in a post by Watermom that you add borax then a part of acid, to offset the alk and ph rise. I don't think I need to worry about that, I am today, still sitting right at 7.2, and 80ppm on alk. My FC is 11, TC 11, CYA still 55ppm. So I am not getting a ph swing like I did last year (it always wanted to be at 7.8 or 8.0. I was going thru acid all season last year (first year with it, so I am assuming there was some stabalizing to be done.
I am running with about 7100 gal of water in my little pool, so I only need to add about 13 oz or so, should I add the acid, or let the ph and alk bump up a notch or so...
also, can I add this while my TC is high ? (still trying to clear it up the rest of the way, by keeping it up near 15ppm overnight)

Thanks again for the help!

ps, without having a borate test in my kit (is it available thru Taylor ?) how do I know what level I am at ? *please dont say take a sample to the pool store... I usually get into an argument with them! **

[chem geek]

As CrisL pointed out, there are TWO different purposes for using Borax. If you add Borax in order to raise pH, then you just add Borax only. If instead you are adding Borax to get to 30-50 ppm Borates for use as an additional pH buffer and an algaecide, then you add a heck-of-a-lot more Borax as well as acid in small portions one after the other (not together). As for how to measure Borates, there are test strips and this is described in more detail somewhere in this thread.

As for your pH, you could just wait to see how it settles out between the lowering pH effect as the chlorine level drops vs. the increasing pH effect from the outgassing of carbon dioxide. If you see that it drifts upwards on its own, then you can just let it do so as it approaches 7.5 or so. If it doesn't move, then you can add a little Borax to bump it up, but that's really up to you, mostly since 7.5 is a little better on the eyes (but just a little -- the salinity probably has a greater effect in terms of "stinging").

Exposure to sunlight (if you have any this time of year) is the best way to reduce CCs in your pool. The higher chlorine levels will help, but sometimes take a while.

Richard

[Watermom]

I saw in a post by Watermom that you add borax then a part of acid, to offset the alk and ph rise.

I don't think it was a post by me.

[darenjones]

my bad, I got my water people mixed up! I meant Waterbear !

[darenjones]

OK, when do I consider clarifier ? or a floculant ?
I have been after the water for about 2 weeks now
FC 5
CC 0
TC 5
PH 7.2
Alk 80
CH <1
CYA 55
temp 75
Water is still slightly cloudy, can see bottom, but not diagonal to other side.

Any suggestions ? kept the chlor at 11-15 ppm (per the CYA shock table) all week until yesterday (5 days)
Any ideas ? Am I missing something ? Plus, I never got a response regarding the borax, and how to properly add... for PH and for Borates ?