This is a follow-on from my previous posts about stains on the walls of my pool.
After searching all over I decided that the only way I could get a bulk quantity of chlorine, unmixed with stabiliser, was to buy 25 litres of liquid chlorine from a local pool shop. They were unable to tell me the concentration but recommended that I put the whole lot in. I did so and it raised the FC to the recommended 'shock' level. I kept the SWG running to maintain it there in the hope that it would bleach the stains. No such luck.
I decided that, when all else fails, there's always brute force and ignorance so I tackled it with a wire brush. Nothing else would touch it. I had to attach the wire brush to an old broom handle in order to reach the lower part of the pool walls. The weather has been hot and humid so I have been hopping in the pool several times a day. Each time I scrubbed a bit more off and now it's looking pretty good.
I will now maintain my chlorine levels around the 3 to 5 mark and hopefully that will stop it re-forming.
Temp = 24C (on the way down from 27-28 over summer)
pH 8.0 so I added 250ml of acid
FC = 3
TC = 3
TA = 100
CH = 150
CYA = 40
Any comments appreciated.