If you read the article about water quality that fishin4cars posted it talks about using Muriatic Acid to bring down the PH but you have to use it sparingly. I little bit goes a long ways. This is the same acid that is used in swimming polls to bring down the PH in the pool water.
I decided to test it to get an idea of how much to use. Here is the results.
I used a 5 gal bucket of water from my pond. The PH was a solid 9.0. After several trial and errors I found that 5 drops of acid will drop the PH from 9.0 down to just above an 8.0. The dropper I used had a rather small hole in it. But the dropper you use may be a different size so you will need to test it but this will give you a starting point and idea of how little acid you will need.
I hope this is helpful.
Bart
I decided to test it to get an idea of how much to use. Here is the results.
I used a 5 gal bucket of water from my pond. The PH was a solid 9.0. After several trial and errors I found that 5 drops of acid will drop the PH from 9.0 down to just above an 8.0. The dropper I used had a rather small hole in it. But the dropper you use may be a different size so you will need to test it but this will give you a starting point and idea of how little acid you will need.
I hope this is helpful.
Bart