A PH of between 6.6-8.4 is considered safe but the optimum PH level is between 7.0-7.8. Ammonia should be 0, even a slight amount can be detrimental to fish.
Pond filters are a good way to allow you to keep a few extra fish. A brief guide for fish per square foot is as follows: 1 goldfish per 3-4 square foot and 1 koi to every 10 square foot. So this means for a 10ftx10ft pond you could house up to 30 average sized goldfish or 10 average sized koi. Depth will also be taken into consideration.
Pond fish are very often over fed and this will contribute to poor water condition. As a guide we would recommend you feed your fish what they can clear in 5 minutes. Water temperature dictates the frequency in which you feed your fish. In warm water (15-30 degrees) fish will be at optimum metabolism and can be fed between 2 and 4 times a day. Too hot or too cold and fish will eat less often and sometimes not at all. A good quality summer food should be fed from around April until September weather permitting.
We stock a wide range of pond fish food in our stores including some of the top brands, Tetra, King British and our own Privilege. From flake to pellet, we have something to suit all pond fish. We also stock test kits.
If you would like any advice on pond fish, test kits or managing your pond please ask in store.