This week, something weird started happening in the bog filter.
The filter is in a 2'x3'x1'deep frame made of 2"x12" lumber. There is one 3' run of PVC pipe, drilled with 1/4" holes, that sits on the bottom smack in the middle of the filter. Gravel is about 10" deep over that, it's planted with bog plants, and water from the pond is pumped through the PVC pipe, comes out the holes, and is filtered by the gravel and plant roots, before spilling over the waterfall into the pond.
The problem is that this week, water started gushing up several inches from the middle of the filter, directed toward the back of the filter. Water doesn't seem to be flowing the full length of the PVC pipe.
I can think of only two things that could cause this problem, and both seem pretty unlikely. Tell me what you think:
1.) Plant roots or dirt have worked their way in through the holes in the PVC pipe and are causing a blockage at the mid point. But this doesn't sound feasible, since water is rushing OUT of the holes, so how could something go IN to them? Also, I've flushed the PVC and hoses from both ends, and it doesn't seem to encounter any clog.
2.) There is a break in the PVC pipe. This also sounds unlikely. Hell, you can't even cut that stuff with a saw, and I don't see how it could crack!
Any ideas on why this water is gushing from the mid point and going towards the back of the filter, instead of toward the lower end with the waterfall?
To figure this out, I'd have to remove all the plants, and then 650 lbs of gravel. Which I already have done TWICE this year, and am not looking forward to doing again. But I do have to do something, as it's severe enough to force water over the edge of the filter, and it will eventually drain the pond if I don't catch it in time.
