Rust mark removal


New member
Aug 8, 2013
I have a pool 40 ft x 20ft irregular shape about 10 years old which is at our house in Southern France. It was constructed with a reinforced concrete structure with a sprayed marble cement surface finish.

About 2 years ago we noticed 2/3 small rust marks which we think was caused by a small pieces of the mild steel wire joining the reinforcing bars together coming into contact with pool water. Originally we used a salt water generator for chlorine production but have since stopped using because we thought that this was making the rust problem worse; we now use slow release chlorine

To solve the original rust problem we drained the pool, cut out the the rust areas and patched the surface. This was successful on the original patch but since then another rust spot has appeared - this time on the side of the pool - leaving a stain 14 inches x 2inches)

I need advice

Can the rust mark be sealed using an epoxy putty rather than draining the pool again? ( fairly expensive in our part of the world)

and can the stain be removed using Ascorbic Acid or Citric Acid?

Any advice really appreciated



New member
Aug 8, 2013
Thanks for the welcome and early response!

The pool volume is about 100 cubic metres - say 25,000 US gallons - as the rust stain is vertical on the wall I assume that the source of the rust is at the highest point of the stain. Is it feasible to hang a container containing the Ascorbic acid in the area of the stain( with the circulation pump turned off - say overnight) ? - rather than dissolved in the whole volume?

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 23, 2009
SouthWest Alabama
Assuming the ascorbic acid is granules you can put it in a sock and rub it on it if it's a localized stain, or you can get some vitamin C tablets and rub them on the stain if they're available.