Odd stains

[derrikm]

I have about 30 very odd stains in my gunite pool that I just can't seem to be able to deal with. Not even sure if they are metal or algae. They are all about 1/8" wide and vary in length from about 1/2" to 5" or 6". They are reddish brown in color, almost look like rust. The stains have been here for the 3 years that I've owned the pool.

Shocking and brushing have had no effect on them. Yesterday I crushed a bunch of vitamin C tablets, put the powder in a sock and placed the sock on top of one of the stains. I even agitated the sock somewhat during the hour or so it was on the stain. This also had no effect.

What do I do from here? The pool is older and finish is fairly rough. Apparently the previous owners had no idea about pool chemistry. I am using the BBB method. Biggest problem is that my water is so perfectly clear that the stains are highly visible.

Test result are as follows:
FC - 6.0
TC - 6.0
CC - 0
pH - 7.2
ALK - 70
CYA - 60
CH - 650 (Yes, 650, fill water is about 500)

I've never had a metals or phophates test done.

I am at a loss as to what to do next. I can try to take a few pics, but not sure how they would turn out being as I would be shooting through a minimum of 3' of water.

Thanks in advance for any suggestions.

[mbar]

IF the vitamin C didn't work, then I am not sure what is causing them either. Have you tried to put a trichlor puck on them? If chlorine lightens them, then it would be organic in nature. The only other thing I can think of is if the plaster is mottleled. The usual way to tell if the stain is from metals is the vitamin C test, or you can try some ph down in a sock on the stain too. If both of these don't work, then my guess would be it is something with the plaster. Welcome to the forum, I wish I could help more. Maybe someone else will be able to give some more advice.

[belldane]

Hi, I have a fiberglass pool that had rust colored stains that I couldn't remove some were from last year. I tried vit c tablets and they didn't work the first time. I don't think I left them on long enough.

What I did this time was in the evening I put the vit c tablets in the pool and push them around with the broom to cover all my spots. Left them there all night and in the morning the stains were gone! Even the ones that were over a year old.

Patty

[ds_girl]

Maybe you didn't use enough vitamin C or leave it on long enough. I had several rust stains from nails that were thrown in the pool during construction of our house. I put a whole bottle of vitamin C in a sock, tied it to the bottom of my long pole and left it sit on the stain for a while. Then I actually scrubbed at the stain with the sock. It took a while, but first the color of the stain changed to more blackish than rust and then went away. I can't believe the help I've received from this forum! I also converted this summer to BBB from Bacquacil and my pool has never looked better! I can't thank enough all the people here who post and help!:)

[snj2k2se]

Is there a tree near the pool? I have a large Maple tree in my back yard that drops some unknown substance (sap?) into the pool periodically. It leaves stains like you describe on the bottom that can't be brushed off.

What I've found to work is letting the water get very still and sprinkling Cal-Hypo directly over the stains. Wait 5 minutes and the stains brush right off. I have a plaster pool so I don't have to worry about bleaching out a liner.

I also have converted to the BBB method this year but still keep some Cal-Hypo around for this reason.

[DogPaddle]

Derrik--we have similar staining in our gunite pool and I attribute it to lawn chemicals. Back in the spring my hubby was broadcasting lawn food granules and though he SAID he didn't get any in the pool :mad: , the very next day the stains appeared. They have been there ever since and no amount of scrubbing, etc. will take them off. (I also noticed similar staining of our concrete driveway and sidewalk. :mad: :mad: ) Hopefully they will eventually fade. (The upside is that we have a very attractive green lawn. )