It has been a while since I added something here. The mixed aquaponics page got dibs on the sand bed experiment (which is going great!!) and I have been immersed in fisheries and aquaculture literature in preparation for a meeting that has just passed. More of a serious job interview than a meeting, but show me a typical interview that has taken over 2 months and is not completed yet.
I digress. I have been tinkering with my old faithful test bed and part of what was accomplished in the addition of the sand bed is (finally) clear water going into the 110 mm pipe. A previous (read failed) attempt to have a one pump and dirty line NFT component was to send the water into a setting tank before it got to the NFT. That did not work. But it did remind me of one of my favourite scientific concepts. Occam's razor, or for the fancy lot, lex parsimoniae. What am I on about? Well, why did the chicken cross the road? To get to the other side. Occam's razor is a wonderful anchor for lofty technical minds like the one I try to contain and keep busy. It reminds us that the simplest answer to the problem, the one with the least assumptions, is often going to be a good bet. A VERY good bet.
Lets put my observation into context. When the bug called aquaponics bit, we were terribly impressed with the idea that you just have to add fish food to water, let the fish eat it and transform it into super plant food, and the rest is history. Fish tank on the one side, jungle on the other. Then fast forward a few months/years and we are fussing over everything. Trace elements this, micro nutrients that. Additives, shortcomings............ is it the pH? Do I need to change food brands? I was going into assumption overdrive with some of my plants. Nutrients stress - just look at those leaves! But my pH is not high enough to lock away the trace elements. Is my food no good? Those shifty rats at ______________ (insert manufacturer's name here), they have cheapened their formula! Actually the answer was quite simple. Look at the muck in the 110 mm pipe you KNEW were not the best design ever. You told yourself a while back to deal with it, but delayed it to get the sand bed finished.
Once the pipe was cleaned and the plant roots given a rinse (I was also impressed that there was NO root rot - definitely another indication that AP is good at harbouring good microbes and suppressing bad ones) the improvement was immediate. Same plants, same food, same pH. Just Occam applied.
Thus Aquaponics remains just that. Forget the fine tooth comb every now and then and enjoy the jungle that comes from adding good fish food to a tank full of water and allowing the fish to turn it into super fertilizer. Do the basics right. All the time.