Searching for more about "Operating Swiming Pools at High PH"...

[PoolDoc]

Your posts has made clear a couple of changes I need to make, on that page, to emphasize or clarify things you are overlooking.

#1 - I didn't make it explicit, but the high end of that range that I've worked with is 8.2, not higher.
#2 - At that time, I was using a color block that allowed measurement to 8.2. The Taylor (and most other blocks I've seen) only got to 7.8. You can only go as high as you can measure -- when you try to go higher than that, you have to remember that your readings above, say, 7.8 do not actually mean 7.8 -- they could be 8.0 or 8.5.
#3 - The most important take-away from that page is NOT "run at high pH", but rather "don't fight your pool if you don't have to do so!" THAT idea is a fundamental element of the BBB Method: if your pool 'wants' to be at 8.1, and you can adjust, do so. But, if your pool 'wants' to be at 7.2, then adjust to that!

It's still too complex to sum up here, but Chem_Geek has laid out enough analysis to offer a reasonable basis for understanding why some pools 'want' to be at one level and other pools 'want' to be at another. When I wrote that page, I knew that different pools 'wanted' different levels . . . and that they were MUCH easier to operate if you let them 'be' at that level, but I didn't know why.

[Sponge1971]

Ok! I get #3. And I remember reading to "not fight your pool", but I didn't realise the subtle recommendations (on that web page) could relate to whatever level a pool chose to reside at.

On 1st fill (I never did test my tapwater...), and for a few days, the k2006 showed my pool sitting at 7.5ish (my k2006 block only shows 0.2th divisions...and my water was between 7.4 and 7.6).
Over the course of a few days I deliberately Boraxed up to 8-ish (my k2006 block goes to 8.0). It's stayed there for a few days since, with no additional chems.
I don't think I've gotten into the ring with my pool yet...actually this seems to be a pretty easy go... (other than the mystery of my teeny CYA readings, despite having dissolved more than the bottle says to...maybe that stuff is worn out?) However, the reality is that swimming time is pretty much over for us up here..other than the 'indian summmer' I'm hoping for. So far, Ms Irene is beating up on all of us and the coolish grey skies are getting old fast...along with the occasional torrential downpours. I realise next years pool season will be a true test of my preparedness and understanding. I've still got alot to read and learn...

I'm going to mix in a bit of Muriatic, to just bring my PH back onto scale..and once 'on scale' I'll leave it alone to see what it does...

Next year will be a clean slate, with proper bather/seasonal loading...hopefully I can leave the 'boxing gloves' in their package...


OH! (I just re-read my reply here and am reminded of something...) The Taylor kit has a nice little spinny water balance calculator wheel. I remember dialing in my very first readings (which were all within the booklet's spec's) and coming up with -0.4 on the dial. I also remember dialing in readings at PH 8-ish and coming up with almost 0.0. But, does any of this 'really' matter to a vinyl pool? I got the impression the Taylor booklet was leaning towards the commercial side of pools...since it's really made for that segment anyway...and they're all concrete and steel and copper...not plastic or vinyl. I also remember noting that I could have adjusted the -0.4 up to 0.0-ish, if I just increased my hardness...but that seemed pointless to my pool. Then I re-read about the high PH methodology...and realized that would bring me closer to 0.0..along with (what I interpreted) easier/cheaper operating.

[waterbear]

As Ben said, when that post was written the relationship between TA and pH was not as fully understood. Main cause of pH rise in pools (when there is no curing plaster) is outgassing of CO2. Your pool is carbonated much like a bottle of soda. That carbonation comes from the TA (bicarbonate) in the water. The higher the TA the higher the higher the carbonation. The higher the carbonation the faster the outgassing of CO2. The faster the outgassing of CO2 the faster the rise of pH to 8.2 to 8.4. If the TA is lower an equilibrium is reached with atmospheric CO2 at a lower point and the pH tends to stay lower.

If you are interested in some of the chemisry behind this then this post will explain it.

FWIW, I run my own pool between 7.8-8.0 (partly because I have 50 ppm borate and the secondary boric acid/borate pH buffer acts in the opposite direction of the carbonic acid/bicarbonate buffer we call TA and keep the pH in that range for an extended period of time.

The "dial" in your Taylor kit is the Watergram and it is a device for computering the Langelier Saturation index, which is one of the calcium saturation indices used for pools. It really is not useful for a vinyl pool. and is often wrongly applied to other surface pools. It can be used to predict scaling conditions BUT the main factor in the mathematical equation behing it is pH SO (drumroll please) HIGH Ph IS THE MAIN FACTOR IN ANY POOL THAT PREDICTS SCALING CONDITONS!. As far as aggresive water conditions, the Langelier Saturation index CANNOT predict whether water will be corrosive to metals at all. It can predict whether water can be aggressive to a plaster finished pool but, once again, the MAIN faster here would be LOW pH (which is usually only a problem on pool runs on either trichlor or dichlor).

In other words, you can play with it but it means nothing to your vinyl pool. Your pH is what is important and your TA is what determines how fast your pH will rise.

Also, a few fun facts about high pH pools. Like I said, it was developed by United Chemical several years bck and they sell a whole line of bromine based pool additives that require a high pool pH AND when it was being recommended most people were trying to force the pH down to about 7.2 or 7.4 and did not understand the roll that TA plays in pH. The misconception (still taught by many in the industry even today) is that higher TA will stabilize pH. Nothing is further from the truth and people found themselves battling high pH and even trying to raise their TA to combat the high pH when in reality they were making the situation worse!

[PoolDoc]

As Ben said, when that post was written the relationship between TA and pH was not as fully understood.

Just so.

I had discovered, as a result installing an ORP-pH controller on some spas at the Hyatt in Atlanta that aeration + pH control would eliminate carbonate alkalinity in 15 minutes. I repeated the process 3x, because it violated everything I'd been taught, and I was still 'drinking the pool industry's kool-ade' at that point. (I'd just become a CPO instructor the year before, and hadn't yet found all the errors in the CPO exams!)

when it was being recommended most people were trying to force the pH down to about 7.2 or 7.4 and did not understand the roll that TA plays in pH. The misconception (still taught by many in the industry even today) is that higher TA will stabilize pH. Nothing is further from the truth and people found themselves battling high pH and even trying to raise their TA to combat the high pH when in reality they were making the situation worse!

And, I'd also discovered that many of the problems reported when people tried to run commercial pools on bleach disappeared when you let the pH drift up to 7.8 - 7.9. It was this, and some related experiences, that led me to began to understand that many of the difficulties people had with pools were artificially generated by the pool industry's focus on a set of arbitrary numbers.

I didn't yet know how pH related to the HOCl/-OCl chlorine curves published everywhere,

(from Santa Barbara Controls, an ORP/pH controller mfg)

but I knew that it once you added CYA, it wasn't what was being shown. Now, of course, Richard (Chem_Geek) has used Wojotowicz's and prior work to create this one:




When I was looking for an example chart to link, I found this unintentionally funny post on poolspaforum:
http://www.poolspaforum.com/forum/in...howtopic=19260
where someone in the pool industry offers to help Chem_Geek to take some of the industry training classes, so he could understand that standard, and very wrong, curve better. What's funny is that, by the time of that post (2009), Chem_Geek knew more about overall analytical pool chemistry than anyone I've every known in the pool business. There were (and probably still are) some PhD chemists in the biz, but all the ones I've talked to are so lost in the 'trees' that they don't even KNOW that there is a 'forest', so they know more of some of the details than Richard does, but still don't understand pool chemistry as a whole.

[Sponge1971]

wow...<boom>...that's some pretty cool/massive replying...Thanks! I supposed to be working outside so I can't digest yet...but I'll get back to yous.

I did, an hour ago, do water test though. Still a pink 8-ish. However I did an Acid Demand test and 1 drop brought me back on scale, to 7.8, so I guess it really was at 8.0. The second drop brought it almost to 7.6. Anyway, I put in about 1/2 of what the booklet recommended for a 5000gallon pool at 2 drops acid demand. We'll see what happens...
I must say I've never seen smoke come out of a bottle before. That Muriatic Acid sure was intimidating. I diluted it in a 5gallon bucket of pool water, and slowly poured it into my skimmer.

I never did a TA test, though. <doh> However, I have done a few over the last days an it's always been the same-ish, around the 110-ish mark. I'll let everything settle, and tonight I'll run another set of tests, just for gags...

[BigDave]

Ben's written a pretty nice step by step on handling Muriatic Acid at http://www.poolforum.com/pf2/showthr...Your-Pool-s-pH

[Sponge1971]

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Waterbear,

- Thanks for the link to 'this post' detailing the chemistry behind TA and PH relationship. All I can say is "huunnhh?" OMG it's been w-a-y too long since I swirled acids and bases to make pretty colors...(and that should explain my chemistry depth...). I guess If I took the time I might get it...but I'll just go with the "yeah, what he said" route.
It' does have me thinking though...can't I just throw a big azz blender in there, outgass all the co2 and let the chips fall where they may? Wouldn't PH & TA & atmospheric co2 come to a final balance and be happy? ... assuming those final levels aren't too nasty? Do us pool people have to keep tweaking PH & TA because they just want to end up being at nasty levels?

- Ok. Forget about the Watergram, for me. But it is fun to spin around 'n stuff .

- I just read Ben's sticky on Alkalinity adjustment. V-E-R-Y cool...and I kinda understand it! I'll be keeping that baby in my bookmarks folder...along with all the other great posts here.

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Ben,

Thanks for the background on what prompted your 'high PH' page. I'm helpless looking at those graphs, but thanks for the fill in. I read the Chem-Geek page. Poor guy, sounds like he's got a huge bruise on his forehead by now... 3 cheers for him though!

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BigDave,

Thanks for the link to Ben's Muriatic Acid handling for Dummies. I must say...I did *exactly* the same things as he had written....<sigh>....ok...ok...so maybe I didn't do 'everything'...'exactly' the same way.. ..But I *did* have my pump running at least!

I'll be sure to smarten up...if I ever have to touch that bottle again.

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For what it's worth:

I ran a full battery of tests tonight, around 10pm. The pool was uncovered all day with the pump running 24/7 (since it's so damn cheep to do so!!! <giggle><giggle> )

Testkit is a Taylor K-2006

Pool water:
TC = 5
CC = 0 (has always been 0, but bio-load has been pretty minimum since day1)
PH = 7.6 (muriatic acid dosing seems to have worked as required)
TA = 110 (this has been the same-ish since day1)
Hardness (not sure what the short form is...CA?) = 100 (this has also been the same-ish since day1)
CYA = not testing yet...still dissolving. My target is 40-ish.

Tap water: (I let the cold only tap run for 10 minutes to pull a good sample from the main line.)
TC = 2ppm
CC = 0
PH = 7.8
TA = 100
Hardness = 100
CYA = not tested, not expecting any...should I be? (hate to waste reagent on that one...stoopid tiny reagent bottles )



After all this great discussion...I'm not going to dink around with TA & PH...unless I have to. I'll let it ride for the rest of this season and see just how much of a fight it puts up. The real battle will come next season...

I still need to settle on a 'good' set/range of values for TA & PH...but I'm sure I'll find that in the forums...

It' s been no harm done, but I am always inspired by efficient and better ways of doing things...even when I don't have the fullest grasp of what I'm diving into.

Thanks for the reset yous guys.

I guess this thread can be closed, if yous want to close it, since my thread originating question has been dealt with. I can always re-ask my above PH/TA related questions in the proper thread...

[PoolDoc]

You really don't need to worry much about either the TA or the CH on a small vinyl pool -- unless they are too high, it really doesn't matter. Don't put a lot of effort into 'adjusting' them.

You do want to keep your pH somewhere between 7 and 8, but otherwise . . .

[waterbear]

That Muriatic Acid sure was intimidating. I diluted it in a 5gallon bucket of pool water, and slowly poured it into my skimmer.

NOT a good idea, even when diluted. It is better to just pour it in the pool after you dilute it and then brush the pool to "mix" it. As an alternative you can pour it slowly into the stream of a return as long as the return is across the pool from the skimmer and not next to it.

[Sponge1971]

Ooops. Ok for the reminder on proper acid addition...
According to Ben's reply, I might not even have to worry about acid again...