Lo folks, thanks for the input so far.
My current pond seems afflicted with a relatively high nitrate level despite the flow-through approach and decent amount of rainfall. I should probably look at increasing flowthrough. Tests this morning showed nitrate at 60-80ppm. No significant nitrite nor ammonia.
@kdh
A single basket will definitely achieve nothing. I was thinking of installing it in parallel, with it being fed by a very low flow of water from the main pond. measuring the quality of the outflow would allow me to gauge if the basket was doing anything at all - at least to the nitrate. This might be a good way for me to tweak how much flow through is actually needed for optimum efficiency of the filter.
@kevin32
Amazing nitrate numbers. How do you do your water change? Do you flush out old water and top up with new, or do you just trickle in fresh water, replacing whatever's been lost out the RDF? I'm turning over my pond 2.5x per hour too. Not seeing those nitrate numbers
My media is 100% cermedia spheres. Tougher than the cubes, but less porous in exchange.
@icu2
I am looking at 30,000 gph or thereabouts going through the shower and waterfall.. Each shower and the main waterfall will be driven by their own pumps for redundancy. The showers will each be fed by 1 pump, with a valve connecting the two in case I need to take one pump offline. The waterfall face will be fed by a single pump. That pump line also potentially forks to a pair of chiller units for keeping the pond below 80F. Output from the chiller units will return near the bottom of the pond for maximum thermal efficiency - if you can call trying to cool an outdoor pond in a tropical country thermal efficiency
@koiman1950
Showers are absolutely great. I never actually intended to install an auxiliary filter since my planned shower/waterfall is already 100% redundant. It just occurred to me that I'd have to dig up that area for the linkage of the waste sump of the pond to a sewage inspection chamber at the back of the property. I figured that if I was going to break earth there, I might as well turn that area into a filter bed instead of filling it back in. Unfortunately as much as I would like to, I can't actually turn that area into more pond surface or I would have no means of doing maintenance on a planting/privacy strip bordering that area.