Aquaponics Update

I'm about 6 months into the aquaponics experiment. My first system, looked great (IMHO) and worked pretty well until it sprung a leak in the grow bed. I'm pretty sure this was in the drain area. I unfortunately placed the drain near a seam in the EPDM, which wasn't in itself a problem except that one side was regular thickness and the other was double thickness where the seem was and I think that caused a tiny leak that ended up making the wood swell and cause a big problem. Lesson learned. I didn't lose any fish, but I had been wanting to try an IBC system anyway. (IBC's are the giant plastic 275 gallon containers that things like bulk pineapple juice and liquid soap are shipped around in). These are a couple of pictures of that system.



I have the fish tank section shaded to prevent too much algae growing in there so it's a bit hard to see in these photos. I cut the 275 gallon container into two sections, an approximately 175 gallon fish tank and a 100 gallon growbed which is filled with hydroton (expanded clay pellets-- very lightweight, easy on the hands). The grow bed is mounted on top of a structure I built for it made out of 4"x4"s and 2"X6"s. It's on casters like the original system. Right now, because the fish need to stay warm I keep it covered in greenhouse plastic. One interesting thing I learned was that, even though the temps in the grow bed get up above 100˚ during the day, the greens don't bolt, presumeably because of the 68˚ water flowing over the roots every half hour. I keep a 250 watt tank heater with a built in thermostat in the fish tank just in cases the water starts to drop at night.

Growing tilapia

conrete reinforcing wire being used as a structure to support the greenhouse plastic

So far I'm impressed with how aquaponics is working out. These plants have no supplements of any kind, they are strictly being fed with fish water.

P.S. Now I'm working on system #3. The 400 gallon pond is nearly complete...

Aquaponics and a tiny pond

I still haven't added the tilapia to the aquaponics system, but I think the tank may have nearly finished cycling this weekend. In the few weeks we've had them, the females have gotten a little bigger but the males have more than tripled in size.

Grow bed about 2 weeks after planting seeds

The plants are doing fantastic in the grow bed. I've been adding small amounts of fish emulsion both to help with the tank cycling and also to provide some nutrients for the growing plants. This picture is about 10 days worth of growth from the last post's picture.

Finally, I've made a tiny pond on the tiny farm! This roughly 45 gallon pond will serve to grow duckweed to help feed the tilapia. I'm hoping to eventually grow 100% of the food for the tilapia on the property. To build it (after my usual sticking my shovel through some irrigation lines and repairing them) I used leftover pond liner from the aquaponics set up, rocks that were already on the property, plants that came free with my tilapia, a handful of duckweed from the fish store ($1.30) and a pair of gambusia fish to eat mosquito larvae ($2.49). Total cost: about $4. I could have gotten the gambusia free from friends with ponds or the city of Phoenix, but this particular fish store (Phoenix Tropical Fish) took the time to really help me with questions a few weeks back so I thought I'd give them some business, even if it's just a couple bucks.

Pond area: BEFORE

Pond: AFTER


I'll add some plants around the outside of the pond when the weather cools down a bit. The duckweed is spreading rapidly and the water hyacinths are blooming, so it's been a pretty good payoff for a few hours of very sweaty digging and rock piling.

Aquaponics progress

The new system is nearly entirely built. I have learned a lot of lessons, on how to build and plumb more efficiently (for way less money!) for next time around. So many parts that I imagined would be easy to find were not, and some didn't even exist. I've kept all my receipts and will update with the way-over-budget total when I'm done and have returned all of the incorrect parts that I bought. :) I will also add a more reasonable hindsight budget for next time!

The system is a roughly 100 gallon grow bed and roughly 100 gallon fish tank. Both are built with 3/4" plywood and reinforced in the corners (top and bottom) and lined with EPDM pond liner. I will probably also add some reinforcement going over the top of the grow bed to keep it from bowing over time. It's all on an old shelving unit my carpenter neighbor built and gave to me when he moved. Very sturdy but added more casters in the middle (you can't see them in this picture) and some extra 2 by 4 bracing just to be extra sure. The system can obviously not be moved around when full, but the idea is to empty the tank (even temporarily) between seasons so it can be in afternoon shade in summer and full sun in winter. When it's in place I have cinder blocks underneath it for extra insurance.



The most simple explanation is that a pump pumps about 40% of the water out of the fish tank to fill the grow bed, when the water reaches a certain level a siphon kicks in and floods the water back into the fish tank. I went with an Affnan siphon for those of you that are interested in those sorts of details. I'll do a more complete post about siphoning in the future.

Looking down into the growbed-- need a little more substrate to fill it up.

The rocks on a plate are a temporary weight to hold down that pipe. The pipe has lots of holes drilled in it to act as a strainer to keep the rocks from entering the siphon, which is inside that pipe. The pipe to the left of that is an overflow pipe (I need to make it shorter). It's simply a back-up in case the siphon ever fails, it will keep the grow bed from overflowing. The other pipe is hooked up to a 35 watt(!) Laguna Max Flo 600gph pump, and carries the water from the tank to the grow bed. I will put some aquarium filter underneath where it comes out to keep too many solids from entering the grow bed. It might be hard to see but the water pipe is zip tied in place in three different spots to be sure it stays in place.

Still a little more fine tuning, but as it is now, everything works how it should. I plan on beginning to cycle the tank tomorrow, it should be ready for the tilapia in about 3 weeks.