Thought I was doing good, metal stains, citric acid.....

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rob.mwpropane

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In The Industry
Jun 9, 2015
213
Baldwin, Maryland
Ok guys, I'm stumped. I read this;
Pool School - Metals in the Water and Metal Stains
and then this artice;
Ascorbic Treatment to rid Pool of metal stains


It worked like a charm, but I went to get in the pool last night, and my eyes were burning and the water is slightly cloudy. Did I use too much citric acid? What would cause this? I mean, I can handle chlorine, but it felt like I was cutting up onions. I did not use a sequestering agent as I've never really had a problem with stains (at least that I noticed) until recently. (It did coincide with the temps dropping latley??, who knows)

My levels are as of right now;
TA - 60
FC - 0
PH - 7.5

On a side note, how does citric acid get "used up" in the pool, is that just a time thing? Just wondering...

As always, thanks guys....
 
rob.mwpropane said:
almost 2lbs citric acid on a 13k AG pool as it was much cheaper
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Yes, but it's not quite the same as ascorbic acid. It typically takes 1.5 to 2 times the amount of citric acid to do what ascorbic acid will do. It also takes about 3 times as much chlorine to neutralize the citric acid. So my guess is, with the 0ppm FC you are reporting, you still have more citric acid to neutralize.

Citric acid is a lot more acidic than ascorbic acid and so, if it's still in the water, it's going to make your eyes sting (think about squeezing lemon juice in your eye...). Also, when citric acid is neutralized by chlorine, one of the by-products of that reaction is chloroform. Chloroform takes some time to get out of the water and it is an eye and mucous membrane irritant. At very high levels, it can cause a chemically induced stupor similar to being drunk.

So, while you saved money on not buying the ascorbic acid, you'll likely spend more money on chlorine to clean up the by products. Also, be careful not to raise your chlorine levels too fast, or else you'll precipitate the metals out of solution again. Did you add a sequestrant?
 
JoyfulNoise said:
Yes, but it's not quite the same as ascorbic acid. It typically takes 1.5 to 2 times the amount of citric acid to do what ascorbic acid will do. It also takes about 3 times as much chlorine to neutralize the citric acid. So my guess is, with the 0ppm FC you are reporting, you still have more citric acid to neutralize.

Citric acid is a lot more acidic than ascorbic acid and so, if it's still in the water, it's going to make your eyes sting (think about squeezing lemon juice in your eye...). Also, when citric acid is neutralized by chlorine, one of the by-products of that reaction is chloroform. Chloroform takes some time to get out of the water and it is an eye and mucous membrane irritant. At very high levels, it can cause a chemically induced stupor similar to being drunk.

So, while you saved money on not buying the ascorbic acid, you'll likely spend more money on chlorine to clean up the by products. Also, becasreful not to raise your chlorine levels too fast, or else you'll precipitate the metals out of solution again. Did you add a sequestrant?
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No sequestrant as I really never had this issue before. If it's the citric acid in the pool I can deal with that.

Does chloroform hover above the water? My eyes were stinging just opening them above the water line, and I never once opened them below...
 
rob.mwpropane said:
No sequestrant as I really never had this issue before. If it's the citric acid in the pool I can deal with that.

Does chloroform hover above the water? My eyes were stinging just opening them above the water line, and I never once opened them below...
Click to expand...

Well, the process of metal removal kind of requires a sequestrant. You see, the low pH and citric acid is what is removing the metals and making them dissolve back into the water. The problem is, when you add chlorine back into the water, it destroys the citric acid and reoxidizes the metals making them stain again. The addition of a sequestrant (such as Jack's Magic Purple Stuff which contains HEDP) is what protects those newly redissolved metals from chlorine oxidation. The downside is, once you have metals in your water, you need to regularly use sequestrant as it breaks down over time.

So, in the end, if you don't add the sequestrant, you're just wasting your time and money as you'll have constant metal staining any time you elevate the chlorine levels.

As for the chloroform, I suppose it's possible as it dissolves in the water and outgasses from it over time, but I suspect the eye burning is really just from the excess citric acid in your water...I really would advise AGAINST swimming until you actually get some FC registering in the water. With zero FC, it's very easy to get an algae bloom and/or bacteria in the water.
 
JoyfulNoise said:
Well, the process of metal removal kind of requires a sequestrant. You see, the low pH and citric acid is what is removing the metals and making them dissolve back into the water. The problem is, when you add chlorine back into the water, it destroys the citric acid and reoxidizes the metals making them stain again. The addition of a sequestrant (such as Jack's Magic Purple Stuff which contains HEDP) is what protects those newly redissolved metals from chlorine oxidation. The downside is, once you have metals in your water, you need to regularly use sequestrant as it breaks down over time.

So, in the end, if you don't add the sequestrant, you're just wasting your time and money as you'll have constant metal staining any time you elevate the chlorine levels.

As for the chloroform, I suppose it's possible as it dissolves in the water and outgasses from it over time, but I suspect the eye burning is really just from the excess citric acid in your water...I really would advise AGAINST swimming until you actually get some FC registering in the water. With zero FC, it's very easy to get an algae bloom and/or bacteria in the water.
Click to expand...

First, I REALLY appreciate you taking the time to type / explain all this. I searched and couldn't find anything that was concrete.

Will the citric acid or chloroform damage the heater / pool / equipment? I'm almost ready to just shut the pool down, and don't know if this is something that I need to take care off, or can wait until next season?
 
The chloroform will not damage anything. It's very likely at a fairly low enough concentration to not be much more than a nuisance. It will go away soon enough on it's own.
 
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