I was out of town last week and my biofilter clogged up which resulted in over half of the water leaking out of the pond. Luckily, no fish were harmed! The pond lost at least 3' - but it's around 4-5' deep.
For the first time in 4 years I emptied the biofilter completely and tried to figure out where the problem was.
I had to take everything out and throw it away. Wasn't a completed set up to begin with. It's a 300 gallon rubbermaid tub, the pump pushes the water from the big bottom pond's bottom drain and it vortexes in the bottom of the rubbermaid biofilter and exits the top into a 4" pipe that feeds the waterfall.
The problem wasn't so much in the set up as it was in the media used in it. I had quilt batting in mesh bags and plastic soft drink lids in mesh bags. AND I put various potted bog plants into the top of the biofilter which had completely jumped out of their pots and rooted into everything. The congestion of their roots is what caused the problem I think.
The plants are all out, the media is all out, the tons of muck are out, and it's just an empty tub with water running through it right now.
I'm going to put a grate over the bottom (not that plastic ceiling stuff which breaks too easily which is one reason the setup wasn't perfect to begin with- I tried the plastic stuff, it broke, and I just set the bags directly on the bottom). This grate will allow the vortex to actually vortex... something it's never done before.
I would like to use polypropylene strapping in the middle. Above the grate but below the overflow into the 4" pipe.
I'll top it off with another grate to ensure that none of the strapping goes down into the waterfall which would be a mess if it got sucked into the bottom drains and pump.
Looking for strapping material around town- Only thing I've found was polypropylene baler twine. They sell it in 10,000 foot sections.
Will that work? It doesn't have the dimples. BUT it does have lots of surface area.
Thanks for your help,