[Russell Peters]

Quote: Originally Posted by nguyen4 hello everybody, my name Nguyen ( new with koi hobby) i has a pond with 1500 gallonand 10 fish 5 over 16" and 5 under 12" my question is why my pH kept go down after 2 or 3 days i did change a water 10/100 or 20/100. it stay 7.2 and go down to 6.6 , 6.4 onetime it down to 5.8 i did add pH up in but it still go down after 4 day salt .05 nh3 is ok anybody have any ildea??? thank you

Do you have a liner pond? pH up is not a permanent buffer so you need to get something that will work more effectively. Calcium carbonate in some form is best.