Hi Graham, My PH is constantly sky high here in Chessington UK, from the
tap, and in the pond. My fish have spawned twice in the last month, they are
in good health and eat normally. As result I have never used a PH adjuster
although I probably should. I suspect you have a problem elsewhere. Have you
tested for ammonia, nitrates, nitrites, etc. I do a partial water change
every few weeks. Avoid total water changes unless it's an emergency. I am
sure you will get more advice from others that are more knowledgable. Good
luck.....Ken

wrote in message
oups.com...
I have had one of the premoulded ponds for approx 3 years now. It is
part of the day in the sun and part in the shade. It has some edging
pavers round the top and runs through an ordinary filter. It has always
suffered from quite a high PH, but this year it is exceptional, so much
so that some of the fish have developed fungus and have died. I am
adding some PH adjuster but this is having little if any effect.
Approximately 1 year ago it had a total water change. What can possibly
causing this high PH and nothing appears to be clearing it.
Graham.