Sunday, October 5, 2014

Aquaponics Update -- October 5, 2014

October 5, 2014 Here is the final prototype and probably the final concrete system I will be making. As suspected, the limits of "cardboard-concrete technology" were pushed to their breaking point. The water reservoir was supposed to be twice as high, but instead the walls ended up twice as thick. The cardboard simply couldn't maintain its dimensions and the concrete expanded horizontally instead of filling in the form vertically. The inner reservoir is scarcely 200mm deep.

It also is prohibitively heavy. It can be picked up, but it must weight at least 70 kg (150+ pounds) or more which is ridiculous and very impractical for urban agricultural applications which need modular, flexible systems that can be easily moved not only horizontally, but vertically up and down stairs as well.

Still, I have both the reservoir and the overhead planter complete. With everything I learned doing the test article and the lower reservoir, I would say the planter came out nearly perfect. It even included a hole in the bottom for drainage (not visible in the picture) that came out perfectly. In fact, it came out so perfect it makes me wonder what smaller projects or systems I can do with concrete without overreaching in size and material limitations.

Plan B?

There is always a plan B. Even as my freshly poured reservoir was still drying in its molds, I knew I would need an alternative to concrete. I already ruled out plastic containers because of potential chemical leaching, but had discovered large fiberglass fish tanks for sale at the massive weekend market, JJ Market, in northern Bangkok. So there is already research and designs in the works. I began researching fiberglass and found several studies that found it chemically inert and without leaching problems unless noticeable delamination occurred.

A quick 3D model of a fiberglass fish tank found at a large local market here in Bangkok, outfitted with wood cladding to provide functional protection from the elements as well as a platform for holding planters. Maybe the planters will be concrete?

As I shop for a suitable sized system, I will cure the concrete system I already have and begin conditioning it for biology. I may leave it inside and test LED grow lights on it as well. The larger fiberglass system will go on the balcony outside.

So the aquaponic project is still on track, and still progressing as planned. The prototype would still have been too small to produce any large amount of food for the planned urban agricultural network we'd like to see grow in Bangkok, so a larger system was always the next step. At least we know what material and in what direction to take that step.

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