Black Algae and Silver

Our neigbour has a saltwater pool. It has black algae, particually in some places where the very thin top layer of plaster has separated from the pool. It is about 18 years old.

Their pool person is using a silver treatment, will this work or could it do harm. I always thought silver was a last resort for bacteria not algae, please enlighten me.

I am aware that higher than normal levels of chlorine say 6 -7 and daily scrubbing can at least keep it at bay. Would it be a good idea to super chlorinate for 3 days?

Also the ph is a little high 7.8 -8.0.

You should get the ph lower before you shock, that I do know. As for a saltwater pool, I'm not sure how that affects the cl level itself, but you need to find out your CYA (cyanuric acid) level because you might need way more cl than just 5 or 6. You can take the cl level up to 20 and beyond (depending on your CYA level), and that is what kills the algae. I can't imagine silver in any form doing this.

The only silver based agaecide I know of is Silver Algaedyn by D.F.Goldsmith. It is a very effective algaecide 'of last resort', IMHO. It is expensive and silver can stain but it does work. I am not sure if it is compatible with SWGs however.