Looking for folks' thoughts on why standing rainwater on our rooftop suddenly has a red/purple hue..
Hey everyone. I live in a small apartment building where the LL recently had our (white) rooftop repainted. Our LL rarely uses licensed professionals, and most plumbing, painting, etc. jobs are either done by him, one of his friends, or some random person that he found...god only knows where. As a result, jobs often are not done properly, and need to be redone, often then resulting in the original problem actually becoming worse, not better. (Sigh....)
Anyway, I'm just curious...what y'all think could explain the following...
The LL had the rooftop repainted, maybe a month ago, and the person apparently used a product called Gaco Roof 100% Silicone Roof Coating. (Whether the person used another product, in addition to the aforementioned one, I don't know...only that I saw a large barrel of the Gaco product, by the rooftop stairwell, after they'd redone the roof....)
Not long after, I started to notice that any time it rained out - and some water remained, pooled, on the rooftop - that the standing water created a reddish-purple area on the rooftop. (This never happened, prior to the rooftop being painted with the Gaco Silicone product. Anytime it rained, any standing water up on the rooftop had a 'normal' appearance and color.)
It also just so happens that...a new, more recent leak from the rooftop into my ceiling directly below has created a similarly dark, purplish-tinged stain, complete with a dark ring that almost looks 'acidic'... While I've had periodic leaks from the rooftop into my ceiling, in the past, they always looked like typical 'leaks', with a light water stain and perhaps a small 'bubble'. But this is the first time I've gotten a dark colored leak/stain in my ceiling.
I can't help but wonder if all of this is somehow related to the new silicone roof coating. But if so, how would that cause standing rainwater to turn reddish purple? Or maybe it's all pure coincidence, timing-wise, and something in the chemical makeup of our actual rainwater has suddenly changed, causing the reddish hue? BTW, this is in NYC....
Thanks!