View Full Version : Absorbic Acid...How much?

05-01-2006, 12:29 PM
As soon as we open our pool, I am planning on using the acid to remove the stains on our liner. How much of it do I need for my 27' AG (48" deep) pool?

Also, If I remember right, I also need to use some Metal Out afterwards. Am I correct?

This is the Absorbic Acid (Vitamin C) I will be getting...http://www.chemistrystore.com/Ascorbic_Acid.htm

05-01-2006, 06:08 PM
Yes, it is most important that you put in some kind of sequestering agent (metal out). You won't need more than the 2 lbs. I would start with one lb, and let the water circulate for about an hour. If the stain isn't gone, then you can add more. Put in the sequestering agent in at the same time. Have you looked under the cover yet? I am just saying that because one year I closed my pool with stains, and opened it to find it stain free! If you have any more questions, please ask.

05-01-2006, 06:21 PM
I have only looked through the skimmer with a flashlight to see if my water was still clear (it was) I could not tell about the stains.

We plan to remove the cover this weekend if I get my Absorbic in by then.

05-03-2006, 07:41 PM
Pool is now filling but I plan on keeping the cover on it until I get the acid/metal out done. I have 2 pounds of the Absorbic acid on its way, I should have it Friday.

If I dose the acid Friday evening, how long should I wait before adding the Metal Out?

How much can I expect this to affect my pH?

I had my fill water sampled for metals today & found both copper & iron in my tap water. Looks like the Metal Out might have to be a weekly thing!

05-03-2006, 08:04 PM
It will bring your ph way down. After a day you can start to bring your ph up, but don't take it any higher than 7.2 for a couple of days. You can add the ascorbic acid, let it circulate for about 40 minutes, then add the metal out - make sure you use enough metal out - and always do the maintenance dose. Metal out won't hurt anything, but if it isn't in there and you get your chlorine high, any metal in your water that isn't binded with metal out will precipitate out onto the pool surface. When you add your fill water, put your hose in the skimmer. Keep up with your chlorine demand so you don't have combined chlorine, and then you won't have to shock. Keep your filter running for 48 hours, don't backwash, and whatever you do, don't shock for at least 2 weeks! Feel free to ask if you have any questions. Good luck, this should work!

05-03-2006, 08:17 PM
Will it hurt for my pH to get too low? How long before it will hurt?

I really appreciate the help!

05-03-2006, 11:15 PM
I'm not sure with a vinyl liner, but I wouldn't let it go too long. That's why I always start to bring it up the next day - if all the stains are gone. It will take a while for it to stabalize, so you have to test it a lot. Check your Alk too, you have to get them both in balance so they become stable. Use baking soda if the alkalilnity is low, and use borax if just the ph is low.

06-17-2006, 07:18 PM
I had Yellow Mustard Alage. The pool store reccommended Yellow Stuff, by Jacks Magic. My water is crystal clear, but there was yellow stain blotches around the bottom of the liner. My pool is 12' X 20", 8,200 gallons. I then went back and they reccommended that I use EZ-Clor - Metal Magnet- $16.99 for a quart. They reccommended I use the quart in my pool. I did and then they reccommended I use 2 pounds of Pool Stain Treat - United Chemicals - Abscorbic Acid. Mix 4 gallons water to 1 pound Abscorbic Acid, shut down pump and pour mixture into pool where the stains are. I did and nothing happened. I was told that the mixture would sink down to the bottom and remove the yellowinsh stains. It did not work. I still have the stains and I have spent over $80 dollars and I still have the stains.

Confused by bad advice.

P.S. Is this problem fixable? I have gotten into the pool and scrubbed the stains with a brush with no help. My wife and kids refuse to get into the pool untill I get rid of the stains.

06-17-2006, 09:43 PM
Drop some vitamin C tablets into your pool & let them sit. If it removes some of the stain then the absorbic acid should work. If not, the acid will not work & you have some stains other than metal.

06-20-2006, 11:36 PM
I ran the test again with the Abscorbic Acid. This time I shut the pump down for several hours and made sure that the water was completely still. I mixed 1 pound of Abscorbic Acid with 4 gallons water and mixed solution well. I gently poured solution over the stains and the stains started to come clean.

I have an 8,200 gallon pool. I need more Abscorbic Acid. Does anyone know a wholesaler that sells this stuff cheap? I paid $10 per pound at the pool store.



06-20-2006, 11:53 PM
Ten dollars a lb is a good price. These are the cheapest I have found so far. Here are two links:


I don't dilute the ascorbic acid with water. I just go around the pool and drop it down the sides with the pump on circulate. I have a 16,500 gal pool and only use 1 to 2 lbs for a treatment. Leave the pump on circulate for about an hour. Make sure you put in a sequestering agent. After an hour, or when all of the stain is lifted, turn the pump to filter and leave it on 24/7. After one day start to raise the ph. After 48 hours start to raise the chlorine slowly - if you have a sand or DE filter put a trichlor puck in the skimmer. DO NOT do this if you have a cartridge filter. Don't shock for at least 2 weeks.

07-01-2006, 02:34 AM
I'm anxiously awaiting my Asorbic Acid in the mail to start removing my stains. The chemical from United is Oxalic (sp) acid, not asorbic. I have the United Pool Stain Treat in my pool now.. after 24 hours the stain is slightly lighter but still there and very ugly. I have a 8400 gallon in ground fiberglass pool and I can' wait to get rid of the stains. I hope it's as magical for me as it has been for others.. I'm sick of this spoiling the look of my pool. The stains are everywhere, lesser on the bottom. I scrubbed the steps with Vitamin C tabs in a sock so they finally look pretty clean.

How long do I have to wait after treating with Pool Stain Treat from United to do the Asorbic Acid treatment? My water is pretty cloudy right now.

07-01-2006, 08:12 AM
I would wait till all of the oxalic acid is gone - when the water is clear. If you are going to do the ascorbic acid, then I would raise the chlorine up high to get rid of the oxalic acid, and then let it fall back down to start the ascorbic acid treatment. It shouldn't take more than a couple of days. Make sure when you do the ascorbic acid treatment you also use a sequestering agent - I don't know if you used it with the oxalic acid - that may be why it didn't work so well. I never used the oxalic, so I don't even know what they reccomend on the container. Feel free to ask any questions you have.

07-01-2006, 02:31 PM
On the Pool Stain Treat (oxalic acid) they didn't even say to use a sequestering agent, but from reading here I knew that I needed one so I went ahead and added Aqua Chem Metal, stain and Scale remover.

Today my water is cloudy, no chlorine. I am going to have to try to get some chlorine in the water this evening.

My problem right now is the alkalinity.. it is way high. How do I reduce it?

The Ph was low so I added some borax and will check again in about an hour.

Also, why do you not shock for 2 weeks after a stain treatment? I think I messed up because I shocked last night, 24 hours after the oxalic acid, trying to get the water to clear.

Please help :confused:

07-01-2006, 08:28 PM
THat may explain why the treatment didn't work. If all of the metals that were lifted off the surface of the pool weren't bound up by the sequesterant and you shocked, the metals would have fallen back out onto the surface of the pool. Often after a stain treatment the water is cloudy and will eventually get clear by raising the chlorine slowly, and keeping the filter running 24/7. Did it say on the oxallic acid not to shock? I know with ascorbic acid you should not shock for 2 weeks. If your alk is high, (I never had that happen with a stain treatment) then you have to keep your ph low and turn the return eyballs up so that the water bubbles on top to aerate the water. You can check the thread about alkalinity - ther is a sticky at the top of the page to explain the process. Don't get discouraged, feel free to ask any other questions you have.

07-01-2006, 09:24 PM
I think my pool is trying to kill me.

I have added a whole box of borax today trying to get the Ph up to 7.2.. so should I just leave it now (I just checked and it is still low) and turn the eyeballs up? I'm going to go back and read your post again carefully.

I added some chlorine and a puck in the skimmer.

How often can I test the water for changes, and hopefully improvements?

This is really sucky to spend the 4th weekend with my pool out of whack :confused: I'm trying not to get discouraged but dang it! All this and I still have stains.

I didn't shock until I was pretty sure the stain treatment wasn't helping... I shocked last night and still had 0 chlorine today. Oh and I had added a bottle of the AquaChem Metal Stain and Scale treat last week before I started all of this... I hope it helped some. The pool walls from what I can tell now look a bit streaky.

Thanks for all your help. I'm new to all of this and trying to learn as much as I can as fast as I can.

Oh, one more thing. My test strips show 3 ppm total chlorine but 0 free chlorine. ???


07-01-2006, 09:25 PM
Oh also, on the oxalic acid it didn't say not to shock and also didn't say to lower chlorine to 0 - but I lowered the chlorine to 0 anyway hoping it would work better.