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Overdose of citric acid


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  • 1 month later...

Citric acid is used to remove staining from pool at a rate of about 1 lb. per 10k gallons. Green pool is  usually from algae and chlorine is what you would use, not citric acid. . Citric acid will also destroy any chlorine in your pool and make it very hard to maintain a chlorine level untill all the citric acid is oxidized. Citric acid will also drop your pH and TA.  Can't really help you without more info.  Full set of test results (not done with strips), pool surface (plaster, fiberglass, vinyl), etc.

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  • 7 months later...

Good info.  This is my situation.  I used about 4 lbs. of citric acid in a 20k salt pool.  It took the stains out but now I can maintain chlorine.  One question.  How long does it usually take for citric acid to be eliminated from pool water. All my level are good except chlorine. Also my pool is cloudy.

 

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  • 4 months later...
  • 6 months later...

Great site!!! I’ve posted it on some pool forums I’m on.

https://www.medallionenergy.com/blog/pool-stain-removal-guide/

Question, in the past I’ve gotten vitamin C/abscobic acid and it removes metal stands for my steps and parts of the liner. It works great, now that vitamin C powder has tripled in price and I see citric acid powder for super low prices. Will this do the exact same thing? And does it work as good as the vitamin C?

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  • 1 year later...

I would imagine “shock” would do the trick.  If the levels of citric acid are high and they break down chlorine levels that is an oxidation process.  More chlorine will eventually oxidize the large amount of citric acid and shock is a strong mega dose of chlorine.  I welcome any correction to my theory, as I’m no pool expert and looking for a solution to my rusty water.  I wondered about citric acid because water softener experts told me to add that to help and seems like it’s work similarly in the pool! Good luck to all as I feel like I need it too!  Lol

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  • 5 weeks later...

So glad to see people having the same issue we are. Added a citric acid mix to remove stains and it worked great.pool was so clear. Didn’t realize it was messing with the chlorine levels. Our pool is now cloudy for a few days. Shocked the pool with two bags and still cloudy, noticed chlorine levels aren’t going up like they should. No more citric acid. Was thinking we had to replace sand in our filter!

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we did shock the pool with two bags of shock for 19,000 gallon pool, did nothing and still waiting for chlorine to balance.  the citric acid worked so well at first, the fiberglass on our pool is yellowing again, not as bad as before.  we will wait til we can get the chlorine in balance.  My chemist brother in law says algaecide and chlorine cancel each other out. the pool supply People told us to use algaecide, but it did nothing for the yellow stain or cloudy water. will just wait.  Thank you for all your helpful comments.

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Ok, time for a bit of knowledge. Citric, Ascorbic, and Oxalic acids (which are the three most common powder stain removers) are effective against iron stains, cobalt spotting in fiberglass pools, and manganese stain but not very effetive on copper stains (it depends on the oxidation state of the copper stain--no effect on reddish or black ones, moderate effect on blue/green ones.

I prefer ascorbic acid (vitamin C powder for a few reasons, Oxalic acid is toxic (even thought it is used on one company's Pools Stain Treatment 😉 ) and citric acid seems to have more of an effect on chlorine levels in my experience. However, all three work.

With that being said the proper way to do a stain treatment is to:

1. DO NOT USE THE POOL UNTIL THE TREATMENT IS COMPLETE, CHLORINE IS HOLDING, AND FILTERS HAVE BEEN CLEANED!

Do it in cold weather since you will be running at low chlorine levels for a while unless you want a green pool! It's also a good idea to add a Polyquat based algaecide or to have a borate level of 50 ppm. Either one will help prevent a green pool. Personally, I prefer the borate. For sand and cartridge filters add a pulp based filter aid to help removed any metals that might precipitate out. For DE filters make sure it's fully charged.

2. Lower FC to 1 ppm or less. You can use a peroxide or thiosulfate based chlorine remover but it might make it harder to get your FC to hold later in the procedure. What I prefer is to just stop adding chlorine for a few days. (If you have a floater take it out, if you have a feeder bypass it, if you have a salt system turn it off).

3a.  IF there are visible stains on the pool surface then turn off the pump and add 1 lb. of citric, ascorbic, L-ascorbic, or oxalic acid for every 10k gallons. Sprinkle the powder in the area of the worst stains. Let sit 24 hours.

3b. IF there is water discoloration add 1 lb per 10k gallons around the edge of the pool and run for 1 hour If you have a sand or DE filter put it on recirculate. After an hour turn the pump off and let sit 24 hours.

4. After sitting brush the pool walls and bottom then turn the pump on.

5. Add 16 oz (half a bottle) of a phosphonate metal seqeustrant such as Proteam Metal Magic or Jack's Magic The Blue Stuff or the The Purple Stuff for Salt Pools for every 10K gallons of water. (There are many other brands out there but you want to avoid ones that are based on EDTA. You want ones based on Phosphonic acid derivatives or phosphonates.)

6. Vacuum pool and then clean filters (backwash sand for 3-5 minues then rinse for 2-3, Backwash and recharge DE, clean cart to removed the filter aid and clean the tank out also.

7. Test and rebalance the water as needed. DO NOT TRY TO BRING THE FC ABOVE 2 ppm and DO NOT SHOCK  because this could cause the metals in the water to come out of solution and restain the pool!

8. IF you have a salt system turn it off until chlorine levels are holding

9. Daily test the FC and add enough to bring it up to 2 ppm. (I prefer liquid chlorine or bleach.) Repeat until your chlorine is holding then slowly bring the chlorine up to desired level over a period of days but DON'T RAISE IT MORE THAN 2 PPM PER DAY OR YOUR STAINS COULD COME BACK! If you have a salt system you can turn it back on now.

10. DO NOT SHOCK FOR 1 TO 2 WEEKS OR YOUR STAINS COULD COME BACK. Personally I prefer 2 weeks.

11. IF you had metal stains in your pool it means that the metals are, for the most part, in your water now. You will need to add a maintenance dose of metal sequestrant weekly at a rate of 4 oz per 10 k gallons. You will have to do this indefinitely unless you completely drain and refill with water that does not have metals.

Stain removed is not easy and it doesn't always work. It really depends on the metal causing the stain and it's oxidation state (chemistry nerd stuff).

 

 

 

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  • 1 month later...

I have a 17,500 gallon fiberglass pool and was using a copper based algaecide for maintenance 2oz every week. It started raising the copper level in my pool and ultimately stained the pool and some white fittings. I had never seen anything like this and thought it was black algae. So of course I added even more copper algaecide that made it even worse. Finally I was told to check for stains by buying some vitamin c tabs and drop a few in to see what effect it had. It was magic so then I read about citric acid and proceeded to put 10lbs in my pool. Got rid of every stain plus chlorine and lowered ph to 6.2. Needless to say I had to put my pump in one end and hose with fresh water at the other end. Things got back to normal about 18000 gallons lit's own. Of course then had to redo salt, cya, and ph and alkalinity returned to normal own its own. Finally started holding chlorine. Now I know. Should have tried 1 lb. of citric acid. It was a real pain. Know what you are doing before jumping into this for stains 

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