Hi All,

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.

Today's results:
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.

Cheers,

John Tennnock

For measuring bleach/liquid chlorine concentration, you can put 1ml bleach in 10 liters (or litres) clean chlorine-free water (that is, 1:10,000 dilution), mix well, and test the FC; it will equal the % hypochlorite in the bleach.
--paulr

Hi John,

Welcome back. Not algea, then? If you weren't able to diagnose the stains, you did better, by getting rid of them. Did you use acid or any type of cleaning agent or just the wire brush?

The numbers look good. If you continue to maintain the pool's balance as reflected in your test results your pool will stay in good shape. Of course, we're saddened to hear about your pool water's declining temperature (smirk, smirk). Better get that last swim in! A number of folks here are ready to see the last of snow and ice (or cold rain and humidity) and want to swim. You'll let them, won't you?

One hemisphere's loss is another's gain.

Greg