You could try getting in contact with the manufactures, pretty much guarantee they would have a recommended pump with the right litres per hour to suit your sluice, not enough water is just as detrimental to gold recovery to much, angels of the boiler box are also just as important as the sluice, no point putting hours of shovelling through if the dirt is not being broken down or washed properly,
On a personal note I like seeing at least 10 plus mill of water over the top of riffles, that tends to make the sluice box act like a river in flood, making the riffles create eddies and dead zones to be able to drop out heavy materials all along keeping the lighter materials flowing out of the sluice box,
Just dwt's personnel opinion
On a personal note I like seeing at least 10 plus mill of water over the top of riffles, that tends to make the sluice box act like a river in flood, making the riffles create eddies and dead zones to be able to drop out heavy materials all along keeping the lighter materials flowing out of the sluice box,
Just dwt's personnel opinion