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

[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...

[chem geek]

Anyway, I put in about 1/2 of what the booklet recommended for a 5000gallon pool at 2 drops acid demand.

From the Taylor booklet I have the half-amount (or 1 drop from the acid demand) in 5000 gallons is 4.6 fluid ounces of full-strength Muriatic Acid (31.45% Hydrochloric Acid). Diluting this amount in 5 gallons of water would have the pH go from -1 (yes, that's negative 1) of undiluted acid to +0.4 so still very acidic. Even pouring slowly into the skimmer doesn't help that much with the pH. Even if you poured at a slow 1 gallon per minute (about 1 cup every 4 seconds) with a skimmer flow rate of 20 GPM (so 1:20 dilution) the pH would still be +1.7 which is still low. pH is a logarithmic scale where every factor of 10 dilution of a strong acid or base solution is a 1 unit change in its pH.

As waterbear noted, you really want to add the acid to the bulk pool water and mix it. As he noted, the safest way is to pour slowly in front of a return flow with the pump running and then to lightly brush the side and bottom of the pool in the area you added it to ensure thorough mixing. In fact, most pool products (acid, chlorine, etc.) are denser than water so if you add them too quickly in one place they can pool at the bottom. For some chemicals such as salt or borates, this might not be a big deal but for acid and chlorine it can. Once mixed, however, such chemicals remain mixed.

By the way, it is this post on this forum where I first put up the chlorine/pH relationship with and without CYA.

[Sponge1971]

I just gotta say...You Guys...like...TOTALY ROCK!