Phosphate problem

Question:

Two problems: 1. How do we keep the rocks looking like rocks, without the build up of algae, etc built up on them? These river rocks sit in the bottom of the pond and on the ledge. We do have plants and two fish in the pond. The pond is a kidney shape – about 250 gallons. 2. What do we do about high pH and phosphate? Our pond people recommended the Phos-X (granuler that you put in the filter -have a pondmaster 1000. The phosphate was still high when we did this (off the scale) so we also added the liquid phos-ban. We have added the pH down too but just can’t seem to get this problem under control. About ready to say we will just live with the problem. We not have pea-green soup nor string algae. We do not have ammonia or nitrite problems. It is really weird – not sure where the phosphate is coming from. We are on city water that has a pH of about 7.6 – 7.8. We have even went so far to empty the pond twice with-in the last 2 months to try and get rid of the problem. Have taken the plants out and got new ones. Don’t know what else to do and the “pond” people here are stumped too. The problem is that we don’t have any idea how long we have had this phosphate problem because we did not know to test for phosphate. I took water in to our “pond” people and they tested the water and said that the reason our fish were getting big ulcers on their side was because of the high pH and phosphate Any help would be greatly appreciated! Thanks patti and don and “The Fish”