I was wondering if I could use lava rock on the bottom and pebbles on the top layer for filter media. It's in a 100 gallon trough, water flows from the bottom up.
Yes it is a upflow, I am running about 3500gph. I run my total pond volume through this once an hour from my skimmer. I also have a bottom drain circuit that gravity feeds 3500gph to a 250 gallon settling chamber and then a 100 gallon moving bed filter.About 150 dollars for a new blower... I accidentally burnt out the blower on my dad's koi pond so now he rigs it with the air compressor. The male adapter is fitted onto the pvc piping and then he just plugs in the air compressor when needed I guess. Is your water flowing from the bottom up? How fast of a flow is this?