Recurring rust spots

[Smelscifi]

I have a half a dozen or so rust spots in my pool. Took the advice of the forum and they easily came off with some vitamin C. But three weeks later, they’re back. Is this just how it’s going to be? Using vitamin C every few weeks? Or is there something else at play.

 

[Texas Splash]

If the spots are returning in the exact same spot, it may be rebar from underneath. If the spots are in random places each time, hard to tell. Maybe something falling in the water from nearby ground runoff, maybe something from a swimmer, or some other source? If it's out of your control, like the rebar, keep the pH well controlled since an elevated pH might help to aggregate the situation. You may even try a sequestrant.

 

[Smelscifi]

If the spots are returning in the exact same spot, it may be rebar from underneath. If the spots are in random places each time, hard to tell. Maybe something falling in the water from nearby ground runoff, maybe something from a swimmer, or some other source? If it's out of your control, like the rebar, keep the pH well controlled since an elevated pH might help to aggregate the situation. You may even try a sequestrant.

They are in the exact same spots as before. The pool is only a couple months old, is this something my pool builder could remedy if its rebar?

 

[Texas Splash]

is this something my pool builder could remedy if its rebar?

Not sure how they would go about repairing it if it is rebar short of draining and resurfacing thee area(s). But I would definitely contact the builder. Let us know what they decide to do.

 

[Smelscifi]

Update for the curious: apparently PebbleTec has been struggling with iron contamination. They will be sending divers to chip out and patch all of the spots under warranty.

 

[Texas Splash]

Wow. I have not heard of this before. Good to know. Hope all goes well for you.

 

[Vegas Mike]

My pool is pebble finish, but not PebbleTec. Half-dozen or so rust spots as described in this thread began four months after plaster completed 30 Jan 2020. Contractor initially claimed I dropped something in the pool (in spite of several spots on the pool wall!). He poured pool acid thru a PVC pipe directly to the spots, and they disappeared for a week, but came back. Now says he will need to drain the pool and redo those spots. Waiting until after this pool season ends. Makes sense to me that it was contamination in the plaster.

 

[Vegas Mike]

Doing a probably dangerous solution. I fill a 50ml syringe with 29% muratic acid, and dive down to each spot and dispense a little acid. This has completely removed most of the spots with one treatment. The couple that recurred needed multiple shots. Last treatment about a month ago, and all spots gone so far. Contractor has made himself scarce. I would not trust him to fix this anyway.