2 Jan 2017

I figured a year-end update is in order given how quiet it’s been at this end – and no, I am not selling the car, hah.

Summed up, I’m burnt out from working on the same (though rewarding) project since December 2007 – 9 years! The years-long design and build, the book, having the engine blow up, the expensive and prolonged rebuild, the recent composite work, the sanding, all combined with our yard being ignored; it all kind of came to a natural decision point after the koi pond literally fell apart.

You know me and projects; I got sucked into the technical aspects; the chance to bring the filtration system up to date, combined with the puzzle of how to do it well at a reasonable cost. The new filter system (drum-type particulate filter and moving-bed bio section) is now operational. To help bring the new system up, the existing bio media was transferred to the new setup from the old filter -the one previously mentioned that’s slowly settling into the ground at a worrisome angle. Until the new pond is ready, the existing pond will utilize the new system. While the new pond will have a gravity-fed filter, the temporary setup uses to the existing pump to push water to the new filter. It’s not optimum but it serves its purpose. With it running for five days now, the good news is that the drum filter works great – and the bad news is that it works so well!

There were two surprises: because the pond has never had a real particulate filter other than a settling tank, there’s all sorts of crap (both figuratively and literally) in the existing system. As a result, the drum filter quickly loads up and cycles the sprayers, as designed, which isn’t a problem. The issue is that the sprayers are loud – like someone next door using a pressure sprayer (I put up a short video on Instagram, see it and other stuff at @midlana1). Additionally, each time it cycles it produces roughly a gallon of yucky water and with it cycling about every 10 minutes, that’s 6 gallons an hour, or about 72 gallons overnight – that’s a big pail! For now I’m putting up with it and as the filter does its job and clears the pond, the cycling will slow though it’s too loud. I need to figure out how to hush it up a bit because it’s just a bit much.

Oh, and after building the drum filter, the drum itself may be modified. While it works, the plastic 55-gallon drum has a large “waste line” (being larger in the middle than than the top and bottom). As a result, the filter cloth took six hours to install due to all the wrinkles and folds. Also, watching it get blasted by the nozzles I worry about how long it’ll last. If a new one’s built it’ll have straight sides with polypropylene sheet for the ends and two layers of stainless mesh to contain the filter element, be it polyester or fine-mesh stainless. The stainless may last longer but there are reports that the wire has microscopic burrs that snag waste that the sprayers can’t dislodge. I’ll probably make it so either filter type can be used, making it so it’s far easier to replace than the six hours it takes now.

Redoing the pond has been a great education in project management and logistics. We don’t have a big yard so I can’t just pile the dirt up in one convenient place out of the way – it’s everywhere. The trick is doing things in the right order so I don’t box myself in. Oh and then there was discovering that we have roots everywhere, looking something like brown carpet under the existing pond liner. The good news is that they’re well-behaved, with them only following the liner but not growing through it.

Pond filtration has changed over the last 20 years and it was a big reason for the redesign. In the old days people used all sorts of media for the biological section. Once popular was lava rock due to its low price and really high surface area. Yeah, it worked great for several years until the bacteria plugged up all the pores making it no better than gravel. People also used pea gravel, again cheap, and an absolute bitch to clean due to the weight (and have you ever tried shoveling rock?!). Over the years, plastic media became popular and “bead filters” were the hot thing for a while. Picture an huge hourglass full of plastic pellets, periodically churned to clean. That worked fine until the pellets got so stuck together that cleaning no longer worked. The most recent iteration is a “moving bed” filter, basically 1000s of barely-buoyant plastic objects in a tank constantly being churned by air injection. It works really well because the air injection supplies the oxygen the bacteria need anyway, the constant motion ensures that the water flowing through the bed is fully exposed to the media instead of taking the shortest path from inlet to outlet, and the constant agitation knocks off the dead bacteria resulting in no channeling or clogging. Shown is the biological container in operation and what one of the bits of media looks like. It’s just a surface upon which beneficial bacteria can grow; an additional 12-cubic feet of the stuff is on order.

Anyway, to keep this remotely car-related, walking into the garage tonight Midlana looked rather menacing with the ducting so a picture was in order. It’ll look much more finished once painted and I know I keeps saying I’ll get around it but with the holidays past (businesses back to work), expect that the ducting will be dropped off at the painters soon.