Backyard Aquaponics
A place to discuss aquaponics

Yes, the diagram doesn't show that very well. The void in the sump is an upside-down round planter, and the gravel is piled up all around it. I do intend to make some kind of gris to spread the water over all the gravel.

I popped the shade plastic off the demo system to look at how the roots developed in there. I find it very interesting to look at this, the roots grew right down into the water under the gravel. Now that the pump is not working anymore I wonder what will happen to the plants, whether they will start getting sick or something due to stagnant water around the roots.

Great pics Dave, now I know why it is difficult when removing the bigger plants in my system

Tore things apart this weekend, the autosiphon "pier" is no more. The siphons had been running with no problems for 1 1/2 years. I made a shelf from the blocks and gathered (netted with solids, waited for the babies to work their way up as the water drained from the net) and put the babies in an aquarium. I was able to figure out how the freecycle aquarium filters matched up and hooked up my Dad's old 30 gallon aquarium too. The little aquarium has about a dozen babies in it. There appear to be two batches, ones that are teeny tiny and others that look a bit bigger - less like eyes with tails.

The single larger one is all by himself in the 30 gallon aquarium. I swear while I was watching them in the sump that he ate one of the smaller ones.

I put the gravel into the sump, and the pumps sit in the upside-down planter where the water is clear. The plumbing goes from the pump right over to the fish tank, through a 3/4" to 1/2" reducer to spray above the water line, pumping a lot of bubbles into the FT. The sump pump is still hooked up to the heat exchanger to send the fish water to the plant operation outside and drain the outside water back down.

The FT overflows into the gravel, then the water works its way to the bottom edge of the planter and underneath it to the pumps. Solids are building up on the surface of the gravel, and I would like to make a solids bucket to gather them before the water goes to the gravel.

My goal now that I have some babies captured is to thin out the big ones, maybe try keeping a small set for breeding, maybe shut down for awhile, and switch to some cold water species (trout? bluegill?). When I do that I may consider moving the tank out to the garage or into the yard, but I'm not sure about trying to keep things out there when everything freezes up solid...

BTW, this is what I have in mind for the next system if I ever get to do it. The controversial part would be the "shallow wetted bed" Think of it like an underground running stream, not flood and drain and not a trickle bed except when solids are being pumped out of the solids bucket.

A tank of some sort, pond liner, gravel, a couple buckets, fittings, pipes, two valves, and one pump and you're done.

Great design Dave. I hope you are able to see it thru. Looks like it would be impressive.

I'm waiting for someone to dare me to build it because the gravel is not wetted enough to handle the ammonia load... Are you my huckleberry GF? (Tombstone movie reference)

Yes Dave!
I was just trying to be nice. To be honest the design looks good on paper but has to many flaws and will never work!
Better luck next time?

Is that the push you desired?
Be good and I'll catch ya next year!

A couple of possible problems I see with the idea DD...

If it's exposed to sunlight... then heat could be an issue...

Algael slime may be another.... and low oxygenation for both the previous reasons could be a concern...

May be dependant on flow rate to some extent... and depth.... just how shallow is "shallow"....

And a shallow wetted bed will definately not process ammonia as well as flood and drain. Sorry

My small system runs sorta like a continuous flow, shallow wetted bed, and it does not stack up in comparison with the big system, either in growth or ammonia processing. Seedlings are a beatch to start as well.

More gravel that gets wetted = better.

But yes it would look cool

I agree with you OBO... but you could get a lengthy argument from another member on that one .....

Tis ok, I have both systems, and I know what is far superior

Thanks for the comments guys. Rope would algae grow in the dark? One of the possible advantages I thought from this would be less water loss, since you're not dumping the water at the top so much, which evaporates tons. This wouldn't mean that the plants couldn't be transpiring to cool as they need to though. Another thing I'm thinking with this is that the plant roots will do some of the work for increasing real estate for the biofilm, and that the plants can work their own way down to where the water is rather than it being pumped to them (once they are large enough to reach). In some ways I'm looking to make the root systems do some of the work for the system, and I'm thinking about ways of just keeping most of the gravel moist but not wet.

There are two modes for this, one is the usual all day long clear water flowing underground thing. The other is that when the valves are switched that the solids are pumped out of the bucket to a pipe with holes, on the top of the gravel, where the solids are deposited and some water will saturate the gravel that is not usually wetted. So it would be like watering the whole bed a couple times per day, like at or ideally a couple hours after feeding times (and at the cooler times of day). From what I've seen of gravel that has been un-wetted for several days (like the round planter I was trying to grow beans in), the gravel stays moist enough to keep the plants going for quite awhile. Rainwater alone would probably keep many plants growing quite fine with the solids that have accumulated in an AP bed that has been run for any length of time. Moist air will also be condensing in the lower sections of the gravel all the time. It's not just dry gravel. That doesn't mean that this can convert ammonia as well, but if the water depth is say 2" and the bed is 12' x 16' (I'm planning for a wide patio thing) then that is like a 240 gallon flooded bed (full of roots too), not including any of the gravel volume above the 2". I guess this could also be called a mostly-moist gravel bed.

If it really went pear-shaped this large bed could be used in a more traditional way, maybe putting a pump in the fish tank, a float switch in the bed, and flooding the bed maybe several times a day using a timer with slow emptying of the bed with the regular continuous pump in the sump area.

I like the idea of trying to do a larger system with a single relatively small continuous pump like what I've been using up to now. I'm interested in larger gravel ratios than just two to one, if this bed were 12'x16'x1' that's 1440 gallons of gravel volume which could support 700 gallons of water if it were fully stocked and run as flood and drain, or this low energy setup could support something less than the max density or less fish tank volume. I'm thinking of a fish tank volume in the 300-500 gallon range, if so that is more like a 3:1 or 4:1 gravel volume to FT volume ratio.

I'll let others have a go DD... brains swimming at the moment... get back to you..

The other thing is to limit heat gain add more plants, maybe even a ground cover like grass or something along those lines, or shaded using viney plants and trellises. Or for unplanted areas put white tiles over them, lots of ways around that problem I think.

G'day Dave, algae enkoys sunlight to grow in so restrict its growing ability by keeping it in the dark - just the application of shade cloth as a cover ensures no algae in my FT.

The ratios pertain to the amount of fish that can be supported with little HSM
If you have more GB space, then work out the stocking density to the amount of water in the system and plant out the GBs a little less dense (or put in more plants that are less nutrient intense)