View Full Version : brown stains along rim of pool, vitamin c does not remove stain, idea?

07-22-2006, 09:51 AM
We have brown stains that extend 4-6 inches under the water line, are on the steps and also there are some bottom stains. I held two vitamin c tablets on the stain to no effect.

what can I try next? thanks, jd

07-22-2006, 11:19 AM
What kind of pool do you have? Do you have any metal in your water? What are your test numbers? If you give us some more info, we will be able to help you better. Welcome to the forum!

07-22-2006, 01:30 PM
thanks for the offer of help and welcome, recently received test kit, here are my current numbers
c 1.5
cc 0
tc .5
ph 7.2
alk 50
cal 120
cya 0

28,300 gallon ig gunite pool

- I'm moving my alk up, 2lbs of baking soda at a time.
- Moving my chlorine to 3...tough without cya
- stopping by pool store for cya today.

07-22-2006, 02:09 PM
You are on the right track - When you test for chlorine the first number is Free chlorine, the second number is combined chlorine, the total chlorine is adding fc to cc. So I don't know where you are getting the .5 - sometimes if you wait a while after adding the drops to test for cc, the water turns slightly pink - this isn't cc. You just want the results of when you first put in the 5 drops. You do need to get cya in the water - put half of what it says to put in on the bottle. You can always bump it up later, and the only way to get rid of it is by draining water. Shoot for 30 - 50, it can take a week for it to show up in a test. You can put it in the skimmer or put it in a sock and tie it near a return jet. You will also want to move your calcium up to 200 - 400. This is necessary in a gunite pool.

As for the stains - they may be organic, which will come off when you get some high chlorine in the water. If they didn't come off with Vitamin C, then my guess would be they are organic. You can also try a pumice stone, or something that will rub a little harder on the gunite. They sell a stain eraser at the pool stores that is good. It can clip on the bottom of a skimmer pole. It rubs the stain off, like a gentle pumice stone. Or you can just bring your clorine level up high and it will fade them in time.

Hope this helps, feel free to ask any questions you may have.

07-22-2006, 02:50 PM
thanks for the tip on cal. that was off my radar. It looks like I'll need a lot. 15.75 lbs moves it up 50ppm...so thats around 45lbs(!) to get into range.

my tc calc was just a math error. my fc had moved up but I forgot to adjust the tc number.

07-22-2006, 04:38 PM
Watch the calcium - I would try adding 10 first and see where you get - I added calcium according to the directions and it went higher than expected. Same as with cya - you can always add more, but once in there you have to drain the water to get rid of it.

07-22-2006, 08:01 PM
Good advice as usual from Mbar (Marie)! You can test to see if the staining is organic by putting a trichlor tab in a sock and holding it against a stain for about 15 minues then scrubbing with a stainless steel brush. If the stain lightens, it is organic and chlorine will remove it, eventually. You can try overfilling the pool so the stains are submerged and supershocking to about 30 ppm to try and bleach them out. If trichlor doesn't have any effect on the stains or makes them darker then they are metals. If vitamen C doesn't lift them there are ways to remove them but they can be lenghty and complicated.
A second thing to try is to put some pH down (sodium bisulfate) in a sock and hold it on the stain for about 10 minutes. If this lightens the stain then an acid wash will remove them. If not then you need to call in the 'big guns'. At this point I would suggest getting a Jack's Magic stain test kit and seeing if one of their solutions will help. Be warned that some of their stain treatments can take weeks to complete and can be expensive.

Also ProTeam makes a sequesterant called Metal Magic that is also able to remove some types of metal stains. It is less expensive than the Jack's Magic products and they have a simple test you can do to see if it will work that only involves a bottle of their product, a sponge, and a plastic bottle. Here is a link to it
It is not as effective as the Jack's Magic products on some kinds of metal stains but is much less expensive and easier to do so you might want to try this first. It will also tell you if the stain is metal or organic. If their sponge test removes the stain then the product should work if you dose it accoring to their directions in the sponge test link.

It is possible that the staining you have is from scale deposit (calcium). The Metal magic might be effective on this (since it will also sequester calcium, which IS a metal) but if it isn't then acid washing or spot application of acid and a pumice stone (and a lot of elbow grease) will help remove them. If the dry acid has an effect on the stains there is a good chance that they are scale deposits.

07-22-2006, 08:16 PM
Great thread waterbear! I have a questions though - the proteam says it will "remove metals from the water" and can be filtered out. Is this true? I thought there wasn't anything to use to remove the metal - you just had to keep it in suspension. Please, Please, tell me that it is true that the proteam will remove metals so they can be filtered out!

07-22-2006, 08:46 PM
Great thread waterbear! I have a questions though - the proteam says it will "remove metals from the water" and can be filtered out. Is this true? I thought there wasn't anything to use to remove the metal - you just had to keep it in suspension. Please, Please, tell me that it is true that the proteam will remove metals so they can be filtered out! As far as I know that one is as true as the tooth fairy and the easter bunny! However, if their process is allowing the metals to fall out of solution (as they put it 'crystalize' ) then the filter WILL collect the precipitate and you will be able to remove some of the metal from the system. I don't know for sure but possibly the stain dissolves and the sequesterant reaches some sort of saturation point and the metals fall out of solutoin but not as stain but as a precipitate. It's possible....We need chem geek here to figure this one out for us. I do know that some of my customers have had good results with the Proteam when ascorbic acid didn't work but it won't work on all metal stains....some of the heavily oxidized copper stains are next to impossible to remove.
I use metal magic in my own pool. I guess I can stop adding it for a while to see if the stains come back or if my water starts testing positive for iron again. But that means I might have to treat the stains again:eek:.....hmmm, have to think about that one to see if I really want to do the experiemnt for the commen good! Marie, I am sure that you of all people understand!;)

07-22-2006, 10:37 PM
Yes I do know exactly what you mean, but I have a friend that I may try it with. She has some staining on her fiberglass pool. I was going to go over and do the stain treatment with ascorbic acid - maybe I will ask her if it is ok to ty the Proteam to get rid of the stains. I am really interested to see what it would be like, but I don't want to "deliberately" get stains on my pool just to try it either. Maybe chem-geek can look into it to see if metals can fall out as precipitate - I know there are ways to do it with water treatment plants - I was reading about it on the internet - but of course I being chemistry illiterate didn't understand most of it.

07-23-2006, 08:57 AM
Keep us posted of the results if you try the Metal Magic!

07-26-2006, 08:42 PM
I loaded 3 tabs into a sock and it did indeed remove a lot of the stain. So the recommendation is superchlorination to 30ppm? How long do I need to maintain that level? Also, is this likely to cause me to need to backwash? I just put a couple of pounds of cya in and I want to avoid backwashing...

07-26-2006, 10:46 PM
It shouldn't cause you to have to backwash.

07-27-2006, 01:22 AM
I ordered Metal Magic today. I am hoping that it is MAGIC! I must have tons of iron in my water. My stains are starting to creep back and I have tons of sequestering agent in the water, Ph at 7.2 and 3ppm Cl.