Need to tackle a (rust?) stain and significant build up of white substance (calcium?)

[black117]

Sorry if this is in the wrong area.

If you've read any of my posts, you will know that I went from being totally hands-off with managing my pool to following the TFP method. This has resulted in my pool being perfect, especially during swimming season. The issue is, over the past couple years, I've seen a build up of a white crystaline substance near my hot tub spill-over as well as a brown, rust colored satin on my tile. I also had a roofing nail drop into my pool over winter, creating a small rust stain. I'm not sure how to tackle these without causing damage. Any thoughts here?

I'll update this thread with photos in a few.

 

[black117]

 

[black117]

In the first photo, a roofing nail somehow managed to blow into the pool last winter where it rusted. It is 6-8" below the water line on a step.

In the second photo, this dark brown stain / build up seems to be leeching out from the concrete / rock from my waterfall. This is the only place it is happening.

In the third photo, you can see significant white build up on the rock fascia around the spillover of my waterfall. My assumption is that rock fascia is not really rock, but some cast material.

 

[black117]

And finally, here are my test results in case anyone cares.

PoolMath Logs

 

[black117]

Anyone? anyone? Bueller?