Yellow Staining, Acorbic Acid Works Well, BUT.....

[chem geek]

People have used citric acid, which is also less expensive, and it seems to work but just takes somewhat longer. I know that oxalic acid is also a reducing agent so in theory it should work, but I don't know how well.

As for preventing algae, one usually adds PolyQuat 60 to the water when doing an ascorbic acid (or citric or oxalic acid) treatment in order to prevent algae from growing during the treatment.

[mbar]

I second what chemgeek said. I have used citric acid and it works well. You just have to use more of it. Here is a link to ascorbic that isn't too expensive:

http://www.msm-msm.com/store/agora.cgi


Here is one for citric acid:

http://www.chemistrystore.com/search...to+Search2.y=0

The rest of your numbers look good. I always use the polyquat 60 when doing the ascorbic acid - especially if the water is warm, you also want to keeep your ph levels at 7.0 to 7.4 while slowly raising the chlorine levels back up. Let us know how you do, and if you have any other questions

[staclear]

How well the Citric Acid works on Gunite walls ? How many pounds I need for 23000 Gallons of water to remove brownish yellow stain due to winter elements.

[mbar]

Citric acid will work, however you will need more citric acid than ascorbic acid. I would start with about 5 lbs of citric acid. Pour 1/2 in and put your filter on circulate. Add enough sequestering agent (metal out) per directions on the bottle. You can add a little more of it later if you need to. Allow the pump to circulate for a couple of hours. If the there is still staining add more citric acid. Once all of the stain is lifted you can put the pool back on filter. Make sure you have the sequestering agent in the water or when you start to balance the water you will just get the stains back. After the stain is gone and you rebalance the water, if the stain returns then you bring your ph back down to 7.2 and add more sequestering agent. Feel free to ask any other questions you have

[pilot-werx]

So the plot thickens........... I had did the ascorbic acid and metal out and was trying to keep the chlorine down... We have gotten about 3 inches of rain in the past two days and the pool is now awful. The water is now milky white to the point where you cannot see the bottom step. So frustrating seeing the water was crystal clear. Any ideas before I get the backhoe and end my headaches? So I have got the chlorine tabs in the skimmer as well as in the chlorinator..

any help would be appreciated...

[Watermom]

Go ahead and post a current set of water testing results also, please.

[pilot-werx]

Here is where I am at with the water...

TC: 10ppm
FC: 10ppm
pH: 7.4
alk:120
cya: 100

My chlorine numbers are not going to be all that accurate because I just dumped two gallons of shock in it an hour ago.

I could care less about swimming in it over the next couple of days so I am hoping that by keeping the chlorine hi I can clear it up...

Where I was keeping the chlorine low for a few days, I added some algaecide to help keep the algae away so I am hoping that is not a problem..

The fight goes on!

[mbar]

Your cya is very high. Is it possible to do a partial drain and refill? You will have to get your chlorine up to 25ppms to shock, and a minimum of 8 just to keep it sanitized. Sometimes after the ascorbic acid treatment the water gets cloudy. A partial drain will help the pool to clear faster, but is your fill water the problem, or do you think the metals came in another way? If it is your fill water you will need to put in more sequestering agent when filling. What is your calcium level? If your calcium level is high and your alkalinity is at the high end you can be getting some fallout from that, which will cloud the water and the only way to get rid of high calcium is to do a partial drain. You can also use skimmer socks. Otherwise you just need more POP - pool owners patience

[waterbear]

People have used citric acid, which is also less expensive, and it seems to work but just takes somewhat longer. I know that oxalic acid is also a reducing agent so in theory it should work, but I don't know how well.

FWIW, oxalic acid is what is used in United Chemical's Pool Stain Treat and Pool Stain Treat spotting bags. I can't really tell a difference in how fast it works compared to Ascorbic acid but Citric does seem to be a bit slower. However oxalic acid is the most toxic of the three with ascorbic acid being the least toxic.

[mbar]

Make sure as you raise your chlorine levels you add more sequestering agent if you see stains coming back. Add the chlorine slowly - that's why I like to add bleach. You can add it in small amounts till you get it where you need it to be.