Can someone help me lower my ph in my fish pond? I have a 1000 gallon fish pond and the ph levels are always high night and day, I keep putting in ph decreaser and nothing happens. I am on a well system water supply and the ph straight from the well is 7.5 but when its in the pond it goes to 9.0 and higher.someone told me to pull the lime stone rocks i had in there because they said the limestone was raising my ph. So i did and there still is no change after 3 weeks and adding more ph decreaser as well. My water also turns green but i do not get any string alge. Please Please Someone help me!