Brown stains spreading

[smallpooldad]

Firstly if you do not have a pool sweeper with brushes you will need to do a lot of brushing while all this is going on. The fact that your pool is at 72 F is beneficial to the chlorine as it is stronger at lower temperatures.

One reason that you may be getting stains is your REAL alkalinity could be too low for a vinyl pool, if you are not adjusting it, please see below.

You can buy vitamin C POWDER from your local health store DO NOT GET the crystals they will not work as they are non-acidic.

You will need 1 to 1 1/2 lbs per 10,000 gals. Keep the pH low, say 7.0 and sprinkle it around the wall. I did mine at a pH of 6.0 in a gunite pool and it worked very well but a number of persons on this website think that 6.0 is far too low, although ascorbic acid has a pH 6.0; at 7.0 I had limited success.

VERY VERY important drop the chlorine to 0, yes zero, before putting the the vitamin c (ascorbic acid) into the pool, or all the the acid will do is eat up the chlorine and not do the work on the stain. You can buy a chlorine reducing chemical from your local pool store. Sprinkle the powder around the walls or near the stains.

If you are worried about an algae bloom put in one quart of Algaeside 60, not 50, 40 or 30 per 10,000 gals. Then immediately add 3 quarts per 10,000 gals of metal or stain treat (not stain removal) to catch the metal stain in solution.

In regards to the filter adding DE helped catch more particles, then again this may be more in the mind than in reality. With a 300 lb sand filter (9,000 gal pool) add enough DE, through the skimmer box, to raise the pressure by 1, this is about 3 cups, add one cup at a time and wait 15 to 20 minutes. Once you have started the ascorbic acid process you may notice, if you have a sand or small filter, the pressure rising dramatically and your filter slowing down. I back washed for 1 minute only after each of the first two 12 hour periods as the filter became blocked.

It is best to first backwash and then COMPLETELY DRAIN the pool after having run the pump for 48 hours non-stop. If you do not the metal will eventually fall out of solution and cause the stains to reappear via deposit.

Refill and bring the calcium hardness up to at least 200 - 250 for gunite, 100 to 150 for vinyl. I think the higher number works better with stain problems although I am not sure why. Some members have suggested that calcium in the filter helps get the metals deposited in the filter and then washed out in the backwash.

Once you refill it is a good idea to shock your pool first with liquid bleach 20 ppm (Ultra Bleach from Walmart is cheap) at a low pH of 7.2 then after 48 hours bring your pool back into balance and FINALLY add 1 quart per 10,000 gals metal out to keep any metal introduced into pool with the new water in solution. Do this once a month, or as Mbar suggests a little say 3-4oz if the stains reappear.

DO NOT SHOCK if you are not refilling the pool. However if you do not drain and refill you will have the ascorbic acid in solution which will eat the chlorine in large doses. It will take lots and lots of chlorine before you can maintain a stable level. This may take 2-5 days of constantly adding chlorine, a real pain.

If you keep the pH between 7.2 - 7.4 (it keeps the metals in solution) you should not have too many stain problems. Keep the REAL alkalinity between 90 and 100 for gunite, 100 to 120 for vinyl, this also helps keep the metals from falling out of solution, using your CYA number to adjust this. Example a CYA of 70 X ph 7.4 adjustment of .30 gives a reading of 21.0. So your alkalinity should read 120 to get a real alkalinity of 99.0. At a CYA of 40 the adjustment is 40 X .30 or 12.0 so your reading should be around 110 to get a real count of 98.0.

ph CyF adjustment

6.5 0.11
7.0 0.22
7.2 0.26
7.4 0.30
7.6 0.33
7.8 0.35
8.0 0.36
8.5 0.38

If your CYA is 70 then you should keep the Total Chlorine between 7-8. Remember it takes 3-5 days for CYA reading to measure correctly as it dissolves very slowly, so do not add more than is necessary.

Do not shock the pool after you are in balance for at least 2 weeks or it may go cloudy. Add Algaecide 60 if you like.

I learnt most of this from Mbar so you have her to thank.

Finally, two finallys, first if you have blackish looking stain streaks these are normally caused by tannin from leaves, to dissolve these you would need to keep the chlorine up at around 30 ppm for 48 to 72 hours. Carefully monitor your pH level to 7.2 and Your REAL alkalinity to 90-100 for gunite, 100 to 120 for vinyl. Running your pump the entire time. Second, you may still need to do the the muriatic clean process but this is more difficult and should only be used as a last resort, I think doing the ascorbic acid process at a pH of 6.0 is better and less dangerous than putting a muriatic mix of say 1 part acid to 3 or 4 parts water directly onto the wall but once again some members may disagree and I have no experience of vinyl pools.

Aloha and good luck.

[smallpooldad]

Cyanuric Acid Correction To Total Alkalinity.

The following is taken from Taylor's "Pool and Spa Water Chemistry" (rev 9/94).

"Total alkalinity is a measurement of both carbonate alkalinity and cyanurate alkalinity present in a sample. Since water balance calculations only use the carbonate alkalinity portion, a a correction (which varies with pH) should be applied to compensate for the cyanurate portion."

They further state: "Note: While Taylor Technologies recommends using the correction, some industry professionals remain skeptical and question its value."

It works for me I seem to have far less variation on a daily/weekly basis if I use the adjustment.

[gerri]

I added half a pound of Ascorbic Acid to my pool this afternoon. Then about an hour later since the stains were still there another half pound. Now I'm out of AA but the stains are lighter but streaky and still there.

Marie, you mentioned that there was more that could be done. I think I'm at that point now. Can you help?

[mbar]

You can use muriatic acid, along with the stain treatment- which will be a much harder project. What is your ph now? How much sequestering agent did you put in? Before you start with the acid, I would let the water keep circulating. Make sure you have your ph down to 7 or 7.2 - you can lower it with muriatic acid, put enough sequestering agent in for a full dose according to the back of the bottle. I always add the whole quart for 10,000 gal. So you should have added the whole quart just to be safe. Let me know if this takes the stains off. If not, I will give you directions for the treatment with the muriatic acid, but you will need more ascorbic acid as well.

[gerri]

I am going out to test the Ph now. If it is higher than 7 I will bring it down.

When I added water yesterday I added a quart of sequestering agent. Then today after the ascorbic I added another quart.

I will post again tomorrow to let you and waterbear know what's happening and how the stains look. Since it's dark and the pool light doesn't work I can't really tell about the stain situation right now.

I have the pump on recirculate. Should i leave it on all night?

I'm going to order more AA in the morning. Whether I need it this time or not I'm sure I will need it at some point.

Thanks for your help!

[gerri]

With my drops kit my Ph looks to be at 6.8 right now. What should I do? Can I add some borax tomorrow?

[mbar]

No, just leave it there, it won't hurt overnight, and it will help to get rid of the stains. You can take your ph up tomorrow using borax if the stains are gone. Let me know.

[mbar]

Smallpooldad is right with all of his information, and has dealt with stains.

On the other hand, if you don't want to do all that he has gone through, or don't have as much staining as he did, there is a way to do it without draining and refilling.

You will need about a half to one pound of ascorbic acid per 10,000 gal. I like to go lighter on it and see if all the stain goes away with as little as possible, because as smallpooldad says the ascorbic acid will eat chlorine up really fast.

You need to get your chlorine as close to 0 as you can (there are products that do this). You can buy the ascorbic acid from the internet - I posted two links above. You don't need food grade, I checked. I have used the ascorbic acid from the first link, but the second link sells it in smaller quantities.

Put the filter on circulate.
Use a cup and go around the perimeter of the pool and drop it down the sides as you go.
Let the ascorbic acid circulate for 1/2 hour. You will be amazed how the stain just disappears before your eyes.

If the stain is not all gone, leave the filter in circulate and add more ascorbic acid close to where you still see stain. Leave it in circulate until all of the stain is gone. (add more ascorbic acid if it circulates for 1/2 hour and there is still stain)

When the stain is gone, add enough sequestering agent for the volume of your pool - more is better than not enough.

Put the filter back on filter and leave it on 24/7.

The ascorbic acid will bring your ph down, after 24 hours you can start to bring up your ph - be prepared it will take a lot of Borax, but make sure you test in between, because you don't want to go any higher than 7.2. After 48 hours you can start to bring up your chlorine. You want to do this slowly. It will take a lot of chlorine - I prefer to use bleach only at this time, and try to take it up to your minimum chlorine for your cya according to the "best guess chart" Do not shock! Do not shock for at least 2 weeks! Make sure you keep your ph low for (7.2) for a week or two - it won't be hard becuase the ascorbic acid will help it stay low. Once your chlorine starts to hold, it means that you have used up the ascorbic acid in the water and it will be easy to rebalance the pool back to your regular perameters.

If you add fill water, add through your skimmer. If you have a DE or sand filter you can put a chlorine puck in your skimmer 48 hours after the ascorbic acid treatment.
Always keep the minimum amount of sequestering agent in the water. If you see stain start to come back, drop your ph back down to 7.2 and add a heavy dose of sequestering agent - it will probably lift the stain off without doing another ascorbic acid treatment

Your water may cloud when you do the initial treatment.

[smallpooldad]

If you do eventually go the muriatic acid wash route and I hope not the following advice given to me by "A Good Pool Maintenance Person" might help avoid a serious problem.

He stated that as the acid is very strong it is a good idea to put soda ash or borax in the bottom part of the pool with water to neutralize it. It could possibly burn out the bottom of your pool with such a concentration of acid. Not a bad idea. Personally I have never tried this but this person stated they had seen pools cleaned this way and the gunite was nearly completely eaten away - scary.

Short story on Borax, 16 years ago I visited the mine which if I remember correctly is in or around Death Valley, it is huge, four story dump trucks look like little toys even the massive dynamiting explosions just appear as puffs of smoke. Worth visiting unless the following happens. We went in July and the temperature was around 115 F. We rode in a bus, upon leaving the mine to return to LA the air-conditioning in the bus broke down, some of the persons from the local Rotary Club were older than 75 and some near 90, they were not in good shape. So most of the afternoon and evening were spent at a hospital that was not too close. So do not go there unless you have A1 air-conditioning, are travelling in Mariah Carey's personal road bus, or have a stretch limo with a refrigerated pool in the back.

Any thoughts on the soda ash borax idea from other members would be helpful.

And finally remember "You can take the iron out the walls but you will never take the iron out of the water." Someone, I think it was my mother, said something like that about a cute girlfriend I had when I was young. It took me 40 years to find out she was right but now all I have to worry about is iron.

[cmcq]

It has taken me a while to get back to this as I've been travelling, had to order the acid, etc. but I'm now ready to do the acid treatment. Good news is the stains haven't gotten worse. I have a couple of questions before I start.

First, I assume the metal, stain and scale out product I tried first is a stain remover, not a sequestering agent. Is that correct? If so, do I need to get jack's magic or sequasol as was descrbed earlier in this thread? If not, is what I added still active in the water or would I need to add more. (BTW, I have backwashed since I added it).

Second, the chlorine is low enough for the treatment but I have a SWG. Should I turn it completely off for the first 48 hours then back on (how high?)

Third, how long do you have to wait before you can swim?

Thanks.