Hello folks!
I just wanted to see if anyone had a situation like mine and therefore some
advice to give. I have a 2 year old, 1500 gallon pond with 6 medium sized
koi. I just began testing the PH level recently and found it very high (over
9). I was told to carefully and gradually add Muriatic Acid to bring the PH
level down. I did and for a very short period of time, brought the PH level
down to about 7. However, it doesn't stay 7 very long and spikes right back
up to nearly 9.

Any guesses on why the PH level doesn't level off?
Thanks in advance for anything you can offer.
Steve