Pool store advice to lower alkalinity - three day muriatic acid dose method

15,000 gallon IG plaster

Alkalinity here is naturally high out of the tap, pool tested at 220ppm. Their test said pH was 8.2, all mine say it's closer to 7.6.

Their advice: 1/6 cup muriatic acid in the water for one hour without the pump running then run pump for 23 hours, repeat, repeat. (Three days total)

Hardness is also naturally high, but a disproportionate amount is magnesium, almost a 2:1 ratio of calcium:magnesium when most waters are 3:1 or 4:1.

I don't see any scaling problems, so I'm not particularly worried about the alkalinity, but I am curious about the suggested method - anyone hear of this one?

it's the 'accepted' method and it doesn't work very well. the idea is to pour a shot of acid in the still pool and the pocket of low pH will cause the carbon dioxide to bubble off....sort of like pouring vinigar on baking soda (which is pretty close to what your are doing!) I have read some descriptions of it where they say you can see the bubbling occur! You need to lower the pH and then aerate if you want to do it so it works!
See this thread
http://www.poolforum.com/pf2/showthread.php?t=191

good way to remove the paint from the plaster.

Or melt a vinyl liner.

It's called the "slug" method and the ONLY way it works is if it inavertently brings you to the conditions that the aeration method uses.

Quote:

---

Originally Posted by CarlD

It's called the "slug" method and the ONLY way it works is if it inavertently brings you to the conditions that the aeration method uses.

---

I thought it was called the "slug" method because the guy who thought it up had the mentality of one!:rolleyes:
(me bad!)

Heh,

I'll live with it. I did turn the jets up so they break the water surface and cause some turbulence, but mostly for the 'water effect'. :p

I received the same advice from our pool store. They said to add a cup of muriatic acid right near the return (I guess that is the closest to jet stream that I'll get). I guess I don't understand the difference between this method and the sticky post method. Is the difference just the aeration?

Our method is precise, not a guess about what seems to work. If the guy who came up with the slug method was wearing a tin-foil hat they'd tell you to wear one of those!

The PoolForum method is
1) You lower pH to 7.0-7.2--since alk and pH are closely linked and move together, this pulls the alk down some.
2) now you aerate to raise pH without raising alk as well--there are reasons why aeration raises pH but doesn't raise alk, but the chemists here can explain it in the china shop. Raising pH with Borax or Soda Ash will raise alk back--soda ash makes it even higher.
3) Lower pH again to 7.0-7.2, again pulling alk down
4) Aerate again to raise pH without raising alk.
5) keep repeating as you ratchet alk down.
6) When you hit your target, aerate to get your pH up and treat your pH normally.

There's no hit or miss, this is how you do it.

Carl, My guess is that your method will work just fine but it's a bit different than Ben's (which Waterbear linked to).

Specifically, you advocate allowing the pH to rise as you aerate while Ben calls for keeping the pH low while you aerate (with frequent testing and adding acid as needed).

As I said, I think that both methods will work but won't it take considerably longer if you let the pH rise repeatedly?

Actually, Ben's method and mine are the SAME. We have refined his wording and the steps a bit to clarify it. We have clarified EXACTLY how Ben's procedure works.

Ben is still the source of this method, which DOES work for clear, definable reasons. It was ALWAYS a racheting-down procedure that performed repeatedly. All that has been is the "why".

carl, From your post above: "...The PoolForum method is
1) You lower pH to 7.0-7.2--since alk and pH are closely linked and move together, this pulls the alk down some.
2) now you aerate to raise pH without raising alk as well--there are reasons why aeration raises pH but doesn't raise alk, but the chemists here can explain it in the china shop. Raising pH with Borax or Soda Ash will raise alk back--soda ash makes it even higher.
3) Lower pH again to 7.0-7.2, again pulling alk down
4) Aerate again to raise pH without raising alk.
5) keep repeating as you ratchet alk down.
6) When you hit your target, aerate to get your pH up and treat your pH normally."

From Ben's post on this (http://www.poolforum.com/pf2/showthread.php?t=191): "

1. "Test your ALK, and record it.
2. Decide what your target ALK is.
   If your ALK is high, due to some past dosing error, target 120 ppm, unless you have some reason to go lower or higher. If you anticipate a continuing problem with high ALK, say due to high alkalinity fill water, target 100 ppm. (These are not magic numbers -- if you have a reason, and understand your options, other values can work as well or better!)
3. Use small doses of acid
   to lower your pH to just above the lowest value on your testkit -- or 6.6, whichever is higher. Do NOT lower the pH to whatever the lowest value on your kit is! In many cases, if you try to do so, you'll ACTUALLY end up with a much lower pH, which can damage your pool. Instead, make SURE that your pH is at least a little higher than the lowest pH value your kit shows. Also, do NOT try to lower your pH all at once; for all sorts of reasons, it's important to do it gradually!
4. Begin aerating.
5. Test your pH AND your alkalinity.
   Continue adding acid to MAINTAIN your low pH until your alkalinity reaches your target value. Once it does, CONTINUE aerating, but allow the pH to rise to the normal level. (If it doesn't rise on it's own after several days, you can add small amounts of borax -- NOT baking soda or soda ash -- to bring it up.)
6. Once both pH and alkalinity are at target levels, stop aerating."

The bold/italics emphasis in both quotes is mine.

I'm not trying to nitpick or start an argument, but those two methods are fundementally different in a practical way. In the first, you allow the pH to rise as you aerate while in the second you actively keep the pH down.

The language of Ben's description is misleading. He's having you add acid continuously because he's ASSUMING you are aerating constantly, which will drive pH up continuously.

The lower levels of pH he prescribes will make the process move much more quickly, but are for a plaster or concrete pool...NEVER run your pH below 6.9 in a vinyl pool.

The process I laid out is not really any different than Ben's. It is a little simpler to understand and implement but it relies on the same underlying chemestry: Lowering pH pulls Alk down, and aerating raises pH without raiser Alk.

I and the other moderators and other experienced posters had the benefit of working with Ben's method and refining it. The ratcheting mechanism is a clearer way of doing the same thing. You SEE Alk fall with each subsequent dosing to lower pH. You SEE pH rise from aeration without raising Alk.

It's not as obvious that this is happening in Ben's description, but it it is. It is the same chemistry at work. They are not contradictory to each other.

I did the aeration method for a few days using a sump pump and by turning the return nozzles up, just to see what would happen. The alk dropped from 220 to 170 but then hung there, using lots of acid in the meanwhile to keep the pH down. It's a plaster pool and the fill water is 235ppm alk, so it's a losing battle. There's no evidence of scaling so I'm going to leave it. From keeping aquariums I've learned, don't fight the water if you don't have to. :p

It's a shame I had to turn the nozzles back down, we sorta liked the water effects. :D

Carl's method is EXACTLY the same as Ben's! It will take a bit longer to lower the alk this way but it is easier for a beginner to do since it involves less testing and ajusting. It is also much safer if you have a vinyl liner pool! The chemistry behind it is identical for each! If you understand Ben's procedure then by all means follow it but be warned that it is much harder to accomplish than the way Carl describes. Both ways will have the same effect. One will just take a bit longer since by lowering the pH then aeriting you will remove some of the excess alk and then you lower the pH again and repeat until you finally get the alk in line. By keeping the pH low and aerating and monitoring the alk you will procede faster but you will need to be testing pH several times a day and adding acid to keep the pH down while you aerate and also you need to monitor the alk once or twice a day!

Quote:

---

Originally Posted by waterbear

Carl's method is EXACTLY the same as Ben's!

I'm sorry, but there's is no way you can describe those procedures as being exactly the same. Please look at the quotes I emphasized in each procedure in my above post.

It will take a bit longer to lower the alk this way but it is easier for a beginner to do since it involves less testing and ajusting.

Seems like that would be so.

It is also much safer if you have a vinyl liner pool!

Only if you're not being vigilant about keeping the pH above the lowest level your test will measure.

The chemistry behind it is identical for each!

Agreed, that but that doesn't make the procedures the same. Maybe I'm being overly pedantic, but Ben warns very specifically and vigorously against deviating from his procedures. I understand the process at the layman level and most who will employ it probably do too, but I think there is a substantial risk of confusing those who are less than thorough with their research by advocating procedures that are demonstrably different.

If you understand Ben's procedure then by all means follow it but be warned that it is much harder to accomplish than the way Carl describes.

I don't see what's particularly harder about it other than it requires a bit more testing.

Both ways will have the same effect. One will just take a bit longer since by lowering the pH then aeriting you will remove some of the excess alk and then you lower the pH again and repeat until you finally get the alk in line. By keeping the pH low and aerating and monitoring the alk you will procede faster but you will need to be testing pH several times a day and adding acid to keep the pH down while you aerate and also you need to monitor the alk once or twice a day!

Again, not particularly difficult; frequent testing is something that's often advocated here.

---

Again, I'm not trying to be pedantic or argumentative but I think there's a substantial risk of confusing the new pool user/maintainer here. Maybe Carl's method is better/simpler/easier to understand/more fool proof/etc., but I think you all underestimate the capacity of the newbie to pick and choose the steps of the procedures they find appealing and end up making a real mess of things.

IMHO, you are nit-picking and I don't see anything constructive coming out of this.

I leave it to Ben to come forward and correct me if I have deviated from his procedure in any SUBSTANTIVE way. I have no qualms with him correcting any incorrect assertions I make.

Ben warns people not to deviate from his procedure because a RANDOM deviation, without understanding what is going on, will result in your alk not being lowered.

We have discussed and advised the ratcheting method many times as a revised version of Ben's original method.

Whether you think his method is simple or difficult is simply from your perspective, not from mine which includes lots of questions from our members. If you don't find it difficult, all power to you, but for those who do, I will continue to recommend the ratcheting method.

Ben's breakthrough was to completely discredit ALL the pool store methods for lowering alkalinity as nothing more than bad chemistry and to propose a method that is based on the actual chemistry of pH and alkalinity, a method that can and does predictably work.

The ratcheting method is NOTHING MORE than a refinement of Ben's breakthrough method, relying completely on the same good chemistry he pioneered.

It's nothing more than that.....

And this thread is closed!

If you wish to continue this discussion you may start a thread in the China Shop--that's where we can argue with greater lattitude.