New pool with appearing brown spots

[Danielw8022]

We have a brand new pool and about 2 weeks ago a brown spot showed up on one of the ledges. I brushed it and some residue ended up on my brush. I showed it to the PB and he said something organic maybe fell in. He squirted some MA on the stain and it slowly faded. Eventually the first stain showed back up but I've been dealing with too much FC so I haven't paid much mind to it. Now this morning I walk out to the pool and I see a second stain in the shallow end this time.

What do you think this could be? I don't think it's algae because I've never been out of ratio on my FC/CYA in fact I've been too heave on FC.

FC 11
PH 7.5
TA 110
CH 325
CYA 80

 

[Texas Splash]

I would first try rubbing a Vitamin C tablet on the stain. Either rub the tab directly on it, or you can crush a few of them up into a thin sock or nylon and try that. Let us know if that works.

 

[Danielw8022]

I tried the vitamin C and it worked!!! Doesn’t that mean I have iron in the water?

 

[Texas Splash]

I tried the vitamin C and it worked!!! Doesn’t that mean I have iron in the water?

Well, it does indicate that whatever caused the stain was steel/iron. If we were concerned about iron in the water, you would probably see more spotting all over or discoloration on white items like the skimmer. But you only seem to have a couple isolated streaks right? Now you discuss possibilities with your builder to see what could have caused it. Is there a chance a pool tool or something fell in or sat in those areas? Any post-fill constructions? Did something get blown into the pool and fall on those areas like fertilizer? Just think about any possibilities. Also ask your builder if there is a chance it's something bleeding through from underneath like rebar or something.

 

[Danielw8022]

I thought about what you suggested but I don't think any of those things could've caused it. Could high FC and PH do this? I thought I read on the sequestrant that elevated FC and PH could do something to the iron.

 

[YippeeSkippy]

Look carefully and see if its possibly shallow plaster and rebar showing thru. That would come under the PBs warranty, I believe?

Other ideas- any work being done on the birdcage? could screw or nail shavings fallen in the pool?

Maddie

 

[Danielw8022]

I don't think it's a screw because one of the spots was on the side of the wall. I also tested with a powerful magnet and got nothing.

 

[Danielw8022]

I looked again this weekend with some googles and I'm pretty sure there is something in the pebble tec that is doing it. So far the vitamin C is keeping things at bay. I hope over time whatever is in the aggregate will stop doing it.