Algae on Walls

[dphill2006]

First off, a big thank you to the community for all the information here! I just purchased a house that had a pool that had been neglected, had a 100+ CYA level, and a ton of algae. With all the info here I was able to get the swam under control.

Over the last week or so I did a partial drain, SLAMed (Or at least as close as possible without a FAS-DPD kit, which I have now), scrubbed the walls and floor like crazy, put an automatic cleaner in, and balanced the PH.

Measurements from last night:

FC- 5.5
TA- 110
Ph- 7.5
CH- 310
CYA-50

My question is how do I get rid of what looks like algae on the walls? Do I just need to keep scrubbing with a wire brush until it all comes off? Will SLAMing the pool again kill it all?

 

[pooldv]

Welcome to TFP!

That is a nice pool! Nice work cleaning it up!

Try rubbing a trichlor puck on the stain to see if it lightens it up. If it does then it is organic staining. Keeping your FC elevated, close to shock level, and brushing with a stainless steel brush will remove the stains over time.

 

[duraleigh]

I doubt it is algae. But first things first, if it is algae elevate your chlorine to right about 10 ppm and hold it there for a week (you don't have to be as picky as the SLAM but try to keep it around 10 ppm) If it is organic, that will take it off the wall. Brush it every couple of days to see if the chlorine is working.

If that has no affect, it is probably calcium scale but I would try the elevated chlorine before you jump to any conclusion that might cost you more money and aggravation. Let us know.

EDIT: do pooldv's test with the puck first!!

 

[dphill2006]

Thanks for the tip about the TriChlor puck- I will give it a try either tonight or tomorrow.

Are there any guidelines as to what is too high of a chlorine level to swim in?

 

[Texas Splash]

If your CYA test was accurately performed by a TF-100 or Taylor K-2006C test kit, then you can swim up to an FC level of 20 (SLAM level).

 

[dphill2006]

Just to be sure, if it does not lighten up after rubbing with a puck, does that mean it is algae and not staining?

 

[Texas Splash]

No changes at all with a puck would tend to indicate the staining might be metal or more probably calcium staining. Your current numbers are not bad, but for those years prior the CSI level could've been through the roof and resulted in those stains from excess calcium.

 

[pooldv]

Here are the tests
Trichlor puck lightens the stain means it is organic, algae, leaves, tannins, etc
Vit C tablets lighten the stain it is metal
Dry acid/sodium bisulfate in a sock dissolves the stain it is calcium scale. A calcium scale stain will usually feel rough to the touch.