Apologies for the huge post, but here goes….. So, 3 months ago I posted my little iavs system that I setup within my current aquaponics system. SLO in a 400L fish tank with a dozen or so goldfish, gravity feeding a 3000x900 square sand bed, set to about 450mm deep. Original post can be found here, https://reddit.com/r/Sandponics/s/XLKGUPMfCV And the 3 month progress from setup was posted at same time, here… https://reddit.com/r/Sandponics/s/IRB82nGWWZ Which now puts it at 6 months old.. so have been asked to share some findings.

Overall for the entire aquaponics system, I have found that while only processing about 1200L/day out of 5000L, through the sand bed component the water quality and suspended solids even in tiny particles has dramatically decreased, as proof, I have always run 3 dwc style buckets to grow cucumbers, rockmellon and capsicum up against a mesh fence wall so they can climb. These buckets are fed with 4mm spaghetti lines which have always blocked up after 24-36 hrs of flow at the junction due to solids building up. It was easy enough to unblock, so.ply shove in some galvanised wire to unblock it. However, since having the sand bed component running they have not blocked up…. Which means over 6 months so ce the last blockage. I have always pretty good water clarity due to the fact that I run sand and gravel filters on each ibc fish tank, but with the addition of the sand bed it's just so much cleaner.

The growth rate in the sand bed co.pared to the regular flood and drain aquaponics beds is superior as well, I planted 3 different rou D's of radish, a red salad variety, plus a few daikon, each round was planted at the same time for the 2 beds, and while the ones in the sand flourished and got the size of a tennis ball for the majority, the ones in the flood and drain aquaponics bed were half the size or even less that of the ones in the sand.

As yet the sand bed has not matured enough to be able to buff the pH of the entire system so that I don't have to do it, but considering I am running approximately 65 X 500g or larger jade perch in my 2 ibc tanks, plus a dozen or so large comet goldfish in the sand bed tank. Add that to the fact that only about 25% of the overall system capacity is running through the sand bed a day, I am not surprised, in fact I would be surprised if it ever did.

Carrots and beetroot did exceptionally well, I only planted 8 seeds of beetroot, but they all germinated and all grew to about the size of my fist, about halfway between a baseball and a softball in size. Carrots I let grow for about 4 months, and I did a harvest and ended up with about 3-4kg. They grew so much that they crowded out the garlic that I also had planted, so the garlic is stunted, and not formed properly, but has formed bulbs, with cloves inside. Sand bed was also used for starting or striking potatoes for another experiment, which failed, but the sand is great for germination purposes ...