Can imbalanced water cause staining?

[cschnurr]

I was asked to help with my neighbours pool (Approx 70,000 litres)
Initial Readings
Cl=0, Combined Chlorine =0 | pH=8+| TA=240 |CH=340 |CYA=55 |
Puck Chlorinator was Empty, Filter Pressure 15, Temperature, likely close to 80F

The water looks much better than the numbers would indicate, so I think I just caught it in time before algae took over.
There was a bit of algae on the bottom, but several areas of dark green stain that look like algae, but doesn't seem to brush away

I immediately topped up the chlorinator with pucks, and turned the dial up to max, and added 13litres of liquid Chlorine (all I had available)
In order to balance the water, I've added 10 litres of MA; in steps, making sure not to drop pH below and 7.2 using the jets pointed up for aeration.
I brushed the liner and vacuumed a bunch of dead algae from the bottom which pushed the filter to 20psi. So I backwashed.
Its looking pretty good, I think it will be perfect by tomorrow.
My question is regarding the dark green stains which are marginally improving, but still evident. Could they be caused by the unchlorinated and unbalanced water? In which case I think they will eventually disappear. Or could they be caused by excess iron or copper in the water?

 

[Texas Splash]

Could they be caused by the unchlorinated and unbalanced water? In which case I think they will eventually disappear. Or could they be caused by excess iron or copper in the water?

If the stains are organic - sure. They should begin to slowly disappear over time. If the stains are suspected to be from iron (i.e. well water), test with a Vitamin C tablet to confirm. Copper would be from pool store products we at TFP never recommend or perhaps a faulty/corroded copper heater core.

 

[cschnurr]

Thanks Texas Splash!

 

[duraleigh]

I immediately topped up the chlorinator with pucks, and turned the dial up to max,

Probably not the best thing to do. With a CYA of already 50-60, you are driving it up further and maybe faster than you want to. I would remove the pucks and chlorinate that pool with liquid chlorine

 

[cschnurr]

Thanks Duraleigh,
When I said top up the chlorinator, I guess I meant it figuratively and put in 3 pucks which historically is its weekly demand. Once I get it all cleaned up, I'll revert back to liquid chlorine as much as possible.