Hi I have just bought a new property with an old house a gorgeous garden and 12 m squared pond. Sadly the previous owner ripped out the filter , pump and fountain system! He left me 10 large goldfish and I am really concerned that I need to prepare for them as the weather warms up. I have been to several aquatic centres and all give me conflicting advice. Apparently I have about 7,000 litre pond........... any advice greatfully received