Mystery algae?

[SDor]

I have a few green stains on my liner. Mostly along a few seams. It looks like algae, but doesn't brush away - even with scrubbing. It's also not slippery, nor is the liner slippery in other areas.

The water has been crystal clear all season and the chemistry is fine (use a Taylor test kit). It doesn't seem to be getting any worse, but I've taken some picture to more closely monitor the situation. There are two faint green lines near where the walls meet the floor.

The pool liner is very old, and on its last season. It used to be dark blue. Could this just be the welds discoloring?

Any ideas?

 

[YippeeSkippy]

No CCs, huh? If not, I wouldn't worry too much about it if you're positive about your test results. <this is where we usually ask for a full set, hint hint>

You could always take a single chlorine puck down and see if that could scrub it off, or if you lay it on a spot for a couple of minutes does it change it?

Maddie

 

[SDor]

Ok, since you will not take my word that the water's fine, here's the test results:

FC: 4
CC: 0
TA: 90
CH: 110
CYA: 30
PH: 7.8

So PH is a little high. CH is low, but it's a vinyl so who cares. Any additional thoughts on my algae/stains?

 

[Mendy48]

Not sure what that could be, but I agree with Maddie...try what she suggested and see if that works. If it does, then it could be algae.

Here's a link that talks about stains in your pool
Metals in the Water and Metal Stains