Help identifying rust / metal stain

[DogtownTX]

Appears to be a metal as Vitamin C worked to fade these, chlorine puck scrubbing did nothing. Just curious if anyone recognizes the pattern this stuff left, whatever it is, and can identify what might have caused it?

There are around 3 clusters of these and they all have stains with that same sort of ovoid/leaf pattern. Each little oval is around 1/2" long. Not sure when these developed so can't correlate to any activity around the house. I've certainly put down fertilizer in the last 6 months, and we had a new roof put on about a year ago (pool is near the house).

 

[Rancho Cost-a-Lotta]

Based on the similar shape and proximity of the stains, it's likely a single metallic object that moved around on the surface, leaving rust stains behind. Put on some goggles or a mask and do some searching. It may have been picked up by a cleaner or maybe it made it a main drain. Check your pump strainer basket.

 

[SoDel]

On a sort of related note, I have a brown stain in my spa that is the exact size, shape and outline of a leaf (likely a leaf sitting in there all winter). Rubbing a trichlor tab on it did nothing. I have since read that leaves (and wood) contain iron compounds which can oxidize and leave an iron stain (reason why a wet glass can leave a dark ring on wooden furniture — so it has been suggested at least). So a couple questions: 1. have you tried AA on the stains? 2. Would it be practical to use oxalic acid on a pool iron stain to convert the iron to iron oxalate and get rid of the stain?

I guess what I’m also driving at is, is it possible your stains are little leaf stains that are behaving as iron stains?

 

[DogtownTX]

Based on the similar shape and proximity of the stains, it's likely a single metallic object that moved around on the surface, leaving rust stains behind. Put on some goggles or a mask and do some searching. It may have been picked up by a cleaner or maybe it made it a main drain. Check your pump strainer basket.

That's an interesting theory, didn't find anything swimming around the other day but going to look again. Based on the pattern it fits with the theory. There are light stain in the shallow end and the darker clusters are in the deep end where the item might have eventually settled. Possible the Dolphin was pushing something around it couldn't pickup.

 

[DogtownTX]

So a couple questions: 1. have you tried AA on the stains? 2. Would it be practical to use oxalic acid on a pool iron stain to convert the iron to iron oxalate and get rid of the stain?

I guess what I’m also driving at is, is it possible your stains are little leaf stains that are behaving as iron stains?

I have tried ascorbic acid via Vitamin C tablets, which did lighten the stains. Could be something organic I suppose, we do have lots of trees around the pool.

I've gone ahead and ordered pure ascorbic acid as my little pills had some elements that caused a stain, the gelatin binders I think. Going to sock some powder on the stains to finish them off. Thanks for everyone's help.