Hi wel li started my pond and did quite a bit of work on the first day the botom base size is 8x4 feet but its 2 feet deep so its around 500 gallon and will be heated with 2 jebo 500watt heaters in winter and will house a jardini i dont know what substrate yet or pond pump size but any help would be great cheers james ps as a young fish keeper loving mfk aslo is 0.35mmpvc pond liner too thinim on a tight budget