PH, Alk, Borax and Acid oh-my

[darenjones]

OK, maybe I am playing the yo-yo game with my pool water chemistry... and after getting my new ps234, I now realize how OFF my "wally world" kit really was... whoa the changes I have had to make.
OK, here are my test results from Thursday, in the AM

FC .5
CC .5
TC 1.0
PH 8.0
Alk 80
CAL >1
CYA 35-40
Water temp 87, air 85
TOD 10am

saw the CC, so I did some more reading, figured out that I wasn't using enough bleach to "Shock" the pool... so I added a 1.4 gal bottle, let er run over night (did this around 4 pm thur). I also vac'd the pool, and brushed around 6.
check on fri morn

FC 1.5
CC 0
TC 1.5
PH 8.0 +
Alk 80
Cal >1
CYA 35-40
Temp 86 air 88
TOD 9am

cleaned the filter, and whoa... re vac'd the pool, and , whoa...
now, onto the ph... slowly added a 1/3 cup of MA, let er run.
check of the water around 4 pm on Fri,
FC 1.0
CC 0
TC 1.0
PH 7.5
Alk 60
cal >1
CYA 30-35 (tested twice)
Temp 89-90 air 93
TOD 4pm

so I added a bit more MA, to bring down the ph a bit more...
got the ph to about 7.2, but it killed the alk, to 40
soooo, I started adding baking soda (mixed in buket, slowly, about 6 lb over 4 hours fri evening.)
got the alk up to 130 (tested Sat Morn) and ph is way way up, 8.2 +

most current from earlier this afternoon
FC 1.5
CC 0
TC 1.5
PH 7.5
Alk 110
Cal >1
CYA 35
temp 87
(oh, btw, my salt, around 400ppm...not sure if this makes any difference, I doubt it, assuming this is from my "soft" water, and from using bleach)


seems as I lower ph, I loose alk, and raising alk I raise ph!!!
Help
please
help

[no1ford]

Which Walmart kit?

[waterbear]

Alk and pH will move together so you want to raise the alk to the high end of where you want to be when the pH is high and then lower the pH to the proper level. Your alk should then be fine. Also realize that at your cya reading of about 40 ppm you will test about 10 ppm higher on the TA than it actually is. I would not worry about 10 ppm but if your CYA is high it can seem to contribute quite a bit to the ALK reading and IMHO, if the CYA is up around 60 or above then the correction for CYA might be worth considering. Easy way to do this (and IMHO, accurate enough) is to subtract 1/3 of your cya reading from your ALK reading when the pH is between 7.4-8.0 and 1/4 of the reading when it is between 7.0-7.2.....close enough for government work.
Getting your ALK to 130 and then lowering the pH was the way to go.

[darenjones]

Which Walmart kit?

The Aquachem kit (the "deluxe" kit)

With the Wally kit (i so affectionately call it) I recieved 'close' readings, close enough I guess to keep my pool clear, but never really crystal clear all the time. for example, the OTO test, as you should read in here, only really gives you an indication that yes, you indeed have some, alot, or no cl in your water. There color bar isn't easy to read. Same goes for the ph. Unless it was 8.0, or 6.8, it is really hard to tell. The best example, is the alk, which when I did a side by side test, I get 180 on the aquachem kit, and 130 on Bens kit, that tells me I have been running a way lower alk for a long time, which explains the amount of acid I have been going through...
ok kit for getting you by for now (and possibly using more chemicals, and possibly draining off the pool later) but, if you are serious, get a decent kit, like Bens.




Waterbear,

Thank you for explaining that, it actually makes sense, especially since I have tested this morning. PH is slowly stabalizing, I have it about 7.4 or so (little less "red" than yesterday) and Alk is still 130-140 (getting 2 different readings, not sure if it is me, or the water, I believe it is me)
2 curious things, 1), the tests in the ps234, the alk, when it turns ever so slightly pink, we should go one more drop, to solid pink, right ? same for the dpd, go till no pink at all ?
2) the Borax, I see in the bleach calc, it says, not for ph, but for algecide ?
I have never had an issue where I have had to raise ph (not in NE fl on municiple water anyway) but using it as an algecide ?

[waterbear]

The Aquachem kit (the "deluxe" kit)

With the Wally kit (i so affectionately call it) I recieved 'close' readings, close enough I guess to keep my pool clear, but never really crystal clear all the time. for example, the OTO test, as you should read in here, only really gives you an indication that yes, you indeed have some, alot, or no cl in your water. There color bar isn't easy to read. Same goes for the ph. Unless it was 8.0, or 6.8, it is really hard to tell.
With any phenol red test you can tell by color and really don't need the comparator once you learn the colors
purple...ph is to high 8.0 or higher
pinkish red... ph is high but ok 7.6-7.8
orange...pH is perfect 7.4-7.5
yellow orange...pH is a bit low to ok 7.0-7..2
yellow...pH is too low below 7.0
The best example, is the alk, which when I did a side by side test, I get 180 on the aquachem kit, and 130 on Bens kit, that tells me I have been running a way lower alk for a long time, which explains the amount of acid I have been going through...
ok kit for getting you by for now (and possibly using more chemicals, and possibly draining off the pool later) but, if you are serious, get a decent kit, like Bens.




Waterbear,

Thank you for explaining that, it actually makes sense, especially since I have tested this morning. PH is slowly stabalizing, I have it about 7.4 or so (little less "red" than yesterday) and Alk is still 130-140 (getting 2 different readings, not sure if it is me, or the water, I believe it is me)
2 curious things, 1), the tests in the ps234, the alk, when it turns ever so slightly pink, we should go one more drop, to solid pink, right ? same for the dpd, go till no pink at all ?
With any titration test like this keep adding drops until one addtional drop produces no more color change then don't count the last drop. for example with the TA test, you add 10 drops and the sample turns red. You add an 11th drop and it turns redder. You add a 12th drop and there is no change in color. Your endpoint is 11 drops.
2) the Borax, I see in the bleach calc, it says, not for ph, but for algecide ?
Correct. It is actually considered to be an algaestat. Won't kill it but helps prevent it. As to whether it actually works or not the jury is still out. You need to get your tetraborate level into the 30-50 ppm range. The calculator might acutally be incorrect and might produce a lower ppm of tetraborates...based on dosage charts for Proteam Supreme. Acid does need to be added to correct the pH in the amount of about 3/4 gallons per 10 lbs of borax. This is an approximation so testing of pH is required to get it in line after the additions. For raising pH just add about a cup at a time and then test the water. Keep records of your addtitions so you can learn how much is required for your pool.
I have never had an issue where I have had to raise ph (not in NE fl on municiple water anyway) but using it as an algecide ?

hope this helps.

[cheshamjim]

Howdy Evan!

I've learned here that there is a relationship between CYA and chlorine, but your post is the first I've read of the relationship of CYA and alkalinity readings. My CYA is very high (120 ppm), so I'm interested in this aspect of it.

I've tried the search function without success, so I'm wondering if you could point me to a thread where this is further discussed.

-Jim

[waterbear]

The ajusted alkalinity is ignored by most people and I haven't really seen it discussed in the forum. My feelings is that it is only something to worry about if your CYA levels are high enough (over about 60 ppm) that they will have a signigificant impact on the ALK reading. The actual correction is pH dependant but the simplifed correction I previoulsly posted is close enough. I just noticed I had a typo in it when I meant to put 1/4 I typed 1.4. I will correct the other post.

Taylor Technoligies sees merit in the ajusted alkalinity and to me it makes sense since the amount of cynaurates in the water will test as alkallinity but are not a part of the carbonate/bicarbonate buffer system that we are trying to measure with the TA test. When the level of CYA is in the recommeded range of 30-50 ppm the amount of error is small and can be ignored. It is at high CYA levels that it changes the ALK reading significantly.