Muriatic Acid versus granular acid

Problems relating to pH and total alkalinity.
Increase ph, increase TA. Reduce pH, reduce TA.
pH chemistry advice and techniques for the pool.
adain24
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Muriatic Acid versus granular acid

Postby adain24 » Sat 25 Jul, 2009 04:53

sounds so delicious! Thanks


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Nu-Pet Granular Greens


darryl2

Muriatic Acid versus granular acid

Postby darryl2 » Thu 10 Sep, 2009 12:22

I just poured 2/3's of a 1lb,6oz bottle of sodium bisulfate to to my above ground pool.It's measurements are 18'x26'x4'.A free water test at a store said my ph was high and chlorine low.And that was all.So I picked some up.I have yet to add chlorine.I have some tablets laying around for the pool,and a 2 1/2 gal container I was going to use for the well water.Did I do this right?
Guest

Muriatic Acid versus granular acid

Postby Guest » Sun 12 Dec, 2010 21:36

I have never heard of anyone recommending mixing chemicals (acid or otherwise) in a bucket of water before adding to the pool. I would not listen to this recommendation as it is BS.
chem geek
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Muriatic Acid versus granular acid

Postby chem geek » Mon 13 Dec, 2010 02:29

The only "bucket of water" reference was in the first post in this thread and that bucket was only being used to mix acid with water. So long as acid is added to the water and not the other way around, then diluting the acid in a bucket of water is OK, though not usually necessary since adding it slowly over a return flow usually provides enough mixing, especially if the pool side and bottom is lightly brushed in the area where it was added.

The part about Muriatic Acid and dry acid behaving differently in terms of TA is bunk, but diluting acid in a bucket of water isnt' a problem. I agree that one should generally not mix chemicals in a bucket (other than dilution with water in the bucket first).
Guest

Muriatic Acid versus granular acid

Postby Guest » Thu 11 Aug, 2011 19:03

Hi I just wanted to confirm that in my inground pool the muriatic acid did lower total alkalinity and I had to use Baking soda then back to acid , etc. When I use PH down I don't have the same problem. This year I didn't have to use baking soda once until I used muriatic acid. So the first explanation was accurate for me and not BS as stated.

Oh and PH always rises in my pool anyway I have a salt system but total alkalinity did not crash until muriatic acid was introduced.
chem geek
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Muriatic Acid versus granular acid

Postby chem geek » Thu 11 Aug, 2011 21:55

No, no, no. Why did you add baking soda? If you have a problem with rising pH, then you do NOT want to raise your TA back up higher. TA is a SOURCE of rising pH through carbon dioxide outgassing. The procedure for lowering TA is described in this post where you will notice that it is a combination of acid addition and aeration at lower pH. There is NO adding of baking soda to raise the TA, even if the TA is below 80 ppm. If your pH tends to rise, as is often the case for saltwater chlorine generator (SWCG) pools, then you want your TA to be lower. If you use 50 ppm Borates in the water, then you can have the TA even lower than 70 ppm because the borates provide additional pH buffering. If you have a plaster pool, you can have the CH be higher to compensate and should also target a pH such a 7.7 instead of 7.5.

The dry acid most certainly lowers the TA just as the Muriatic Acid does, but perhaps you didn't use as much dry acid. If you used too much Muriatic Acid then that would obviously lower the TA more, but outgassing of carbon dioxide would bring the pH up again eventually so the key is to lower the TA level and KEEP IT LOWER. You do NOT want to raise it by adding baking soda.

There are thousands of pool owners with SWCG systems who have significantly lowered the rate of pH rise in their pools and the amount of acid they need to add -- they did this through the combination of lower TA, higher CYA, and use of 50 ppm Borates as described in Water Balance for SWGs.
Alfonso

Muriatic Acid versus granular acid

Postby Alfonso » Tue 01 Jan, 2013 18:56

What is the chemistry involved in the action of sodium bisulfate to lower pH in a pool/spa?
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Muriatic Acid versus granular acid

Postby chem geek » Thu 03 Jan, 2013 11:01

NaHSO4 ---> Na+ + H+ + SO42-
Sodium Bisulfate ---> Sodium Ion + Hydrogen Ion + Sulfate Ion

The solid sodium bisulfate dissolves in water to release hydrogen ions and these lower the pH. You will notice that you get leftover sodium and sulfate ions as a result. Compare this against using Muriatic Acid which is usually 31.45% Hydrochloric Acid which is

H+ + Cl-
Hydrogen Ion + Chloride Ion

So with Muriatic Acid, you don't get sulfates and only get chloride ion (i.e. a component of sodium chloride table salt). If you use a lot of acid and build up sulfates to a high level, then this can become damaging to plaster surfaces.
Guest

Muriatic Acid versus granular acid

Postby Guest » Sun 12 Jan, 2014 23:07

I would not worry about TA being at 150 as long as your pH is in a good range 7.2-7.6 then all good. You will find keeping your pH in a good range with the addition of acid (dry or liquid) will bring down the TA naturally so having high TA is usually a good thing. One less thing you have to balance in your pool.
diddlyD

Re: Muriatic Acid versus granular acid

Postby diddlyD » Tue 15 Aug, 2017 18:52

Mr. DARTH DOUGY, I was ever so pleased to find your well detailed explanation on this subject mainly as it pertains on how to effectively lower PH "without" lowering TA that otherwise would utimatley results in a YoYo cycle effect that's senceless. I can attest to the fact that "Dry Acid" did not lower my TA only my PH and I was done. in fact, my TA actually had a very slight rise 10ppm. My PH has remained stable since for several days now. :) I would not recommend using Muriatic Acid as the ideal way to lower PH alone. Although Dry Acid costs more than Muriatic Acid you won't spend as much on chemicals in the long run as you won't endure the lowered TA and ultimately spike in PH again and have to add more chemicals on this endless cycle. IMHO, focus on keeping PH balanced as the priority and then TA should be easier to maintain.
diddlyD

Re: Muriatic Acid versus granular acid

Postby diddlyD » Tue 15 Aug, 2017 18:52

Mr. DARTH DOUGY, I was ever so pleased to find your well detailed explanation on this subject mainly as it pertains on how to effectively lower PH "without" lowering TA that otherwise would utimatley results in a YoYo cycle effect that's senceless. I can attest to the fact that "Dry Acid" did not lower my TA only my PH and I was done. in fact, my TA actually had a very slight rise 10ppm. My PH has remained stable since for several days now. :) I would not recommend using Muriatic Acid as the ideal way to lower PH alone. Although Dry Acid costs more than Muriatic Acid you won't spend as much on chemicals in the long run as you won't endure the lowered TA and ultimately spike in PH again and have to add more chemicals on this endless cycle. IMHO, focus on keeping PH balanced as the priority and then TA should be easier to maintain.
diddlyD

Re: Muriatic Acid versus granular acid

Postby diddlyD » Tue 15 Aug, 2017 19:44

diddlyD wrote:Mr. DARTH DOUGY, I was ever so pleased to find your well detailed explanation on this subject mainly as it pertains on how to effectively lower PH "without" lowering TA that otherwise would utimatley results in a YoYo cycle effect that's senceless. I can attest to the fact that "Dry Acid" did not lower my TA only my PH and I was done. in fact, my TA actually had a very slight rise 10ppm. My PH has remained stable since for several days now. :) I would not recommend using Muriatic Acid as the ideal way to lower PH alone. Although Dry Acid costs more than Muriatic Acid you won't spend as much on chemicals in the long run as you won't endure the lowered TA and ultimately spike in PH again and have to add more chemicals on this endless cycle. IMHO, focus on keeping PH balanced as the priority and then TA should be easier to maintain.


I would like to make a final comment: Although my experience started with my TA on the very low end of the scale at 70ppm while my PH was too high, after adding Dry Acid it resulted in a slight "increase" to my TA now at 80ppm, which was fine; on the other hand, someone else has reported their experience with Dry Acid to lower their PH also lowered their TA "BUT" the difference was their TA started out on the other extreme with very high TA. So in conclusion, I believe TA is self adjusting in response to the PH changing not directly due to direct effect from the Dry Acid, so if the TA on the high side prior to adding acid it can be lowered and just the opposite can see an increase in TA.
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Re: Muriatic Acid versus granular acid

Postby Denniswiseman » Fri 18 Aug, 2017 17:39

Use these chemicals to balance your water
Liquid chlorine (sodium hypochlorite or plain bleach)
Muriatic acid (hydrochloric acid) to lower pH and TA
Bicarbonate of soda to raise TA
Aeration will raise pH only
Soda ash will raise pH and TA

This is proven and used by thousands of pool users check out www.troublefreepool.com
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Re: Muriatic Acid versus granular acid

Postby DittlyD » Sun 08 Oct, 2017 21:23

I read the above posts and don't have that same experience at all with using dry acid to the most part. The dry acid (PH down) I use is also 95% sodium Bisulfate. My TA does not or barely moves when adding "dry" acid to lower PH from 8 to 7.6 or 7.4 which usually takes about 1 1/2 cups according to the Taylor test kit Reference Manual (I highly recommend using). Today for example, PH was 7.8 not quite 8 and I added enough acid to bring it down to 7.4....TA did not change at all, still at 80. But when my PH got real high 8+ one time, I did see a rise in TA to about 90-100 and it did adjust down with the PH but I also added a lot more Acid to get the PH down to 7.4 that time. So maybe the difference here is how high the PH has to get to effect TA changes up and down when using higher doses of dry acid required to adjust the high PH down.

I just sprinkle the acid into circulating pool water a little at a time that's it (wearing protective gear of course) dissolves immediately. I use liquid chlorine in a feeder that dispenses into the pool water based on the pump running at night and adjusting PH "down" goes hand in hand with using liquid chlorine as the sanitizer; SWG I hear are even worse when it comes to high PH issues. So now what I'm hearing here is if my TA were higher than it is, my ph might be more stable, but I'm not sure what "stable" exactly means, a day; a week or never having to adjust the PH again? Maybe I already have stable. I thought I read somewhere that keeping TA on the low side stabilizes PH better. I do realize TA is a buffer to PH but is it better lower or higher; I'm at the low end of the OK range with 80 right now (I read getting it down to even 70 would be better for PH stabilization).

I'm currently adding PH down once to twice a week depending on when I add fill water (aeration). I see to many minuses for using Muriatic Acid mainly because it has very caustic fumes which most people pour right into the pool water that is so strong if not careful can stain the pool plaster (I don't have a diving pool with 12 ft deep areas) along with the instability of both PH and TA to save a perceived dollar doesn't pass the test for me. I also have not had to add any shock treatments but my water is not exposed to high levels of contaminates either. I hope another posted view is well excepted!
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Re: Muriatic Acid versus granular acid

Postby Denniswiseman » Mon 09 Oct, 2017 02:27

If you are currently reducing your pH up to twice a week then you may be aerating your pool water (fountain, infinity edge, waterfall or other aeration) Failing that your TA is to high, keep reducing it untill your pH stabilises
Each pool is different and the recommended levels suggested by the industry aren't always relevant to individual pools
Such as Chlorine / CYA Chart when the industry standard is 2-3ppm

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