Ian is right; read the thread called "Live Water? Need info on pumps" under Railway Design. This topic has been thouroughly discussed in the past few days.
Tom Trigg
We have already just had a section on this matter; suggest that you look it up, as its got some very good info in it. I am a new person in this area myself and i don't know much about it at all. I do know a fair bit about saltwater swimming pools though.
Rgds ian
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