Simply Koi and More Koi

Hi all,

Another pond construction question for you...

Whats the maximum gallonage 1 bottom drain can cope with? I know a lot depends on the type of filtration being used.

At what size do you need to install a second bottom drain.

regards.....Martin.

If my memory is correct then I think it's a little over 3,000gph for 4" pipe and a properly fitted cover (I seem to remember 3,250gph as the exact figure) when the water is flowing under gravity feed. If it's pumped through the 4" pipe then it will be much higher than that, but I don't know the exact figure.