Backyard Aquaponics
A place to discuss aquaponics

The idea here is that the air stone comes in from the side or below, and bubbles keep the solids from leaving the container.

Instead, the flow out of the container would stop, then the water would rise, then the bubbles coming out of the air lift would get larger and stop, then a siphon was formed at the outlet and it drained as a siphon until the siphon stopped. Only then did the bubbles come out of the air lift again.

I think what is happening is that as the bubbles are stalled, that they consolidate and get larger. They form a plug, keeping water from going out of the outlet. Not until the water pressure overcomes the large bubble plug did the siphon start, pulling the bubbles with it.

As I type this, maybe it was a side effect of the horizontal pipe to the outlet, where the bubble got larger. I had wondered if putting the air stone below the water outlet, so that the bubbles go straight up might help. Or, having the bubbles come in above the water outlet, so that they don't get pulled out the side so easily. But it appears that you can't keep the bubbles from getting fat in this situation.

Since that failed I went ahead with trying to make a settling cone and aerated sludge-type digester, like here:

http://www.environcorp.com/services/was ... tem%20(AIS)&id=5421&link=ADVENT%20Integral%20System%20(AIS)

It went surprisingly easy. I used the same kind of round trash can as for the Rendezvous Mark I biofilter. I made the settling cone from PVC flashing (for construction like to keep rain from going behind a header board). I did it completely ad hoc, just took the rolled up section and trimmed it smaller, roughly marked the max radius, marked another point at the lower point, drilled holes at those points, held them with pop rivets (aside - since I was a kid I always wanted to use pop rivets). Riveted more to make the seam tighter, then cemented it as best I could (cement seemed to be kind of frozen or dried out but still kind of worked).

The outlet is a 3/4" electrical conduit fitting, with a rubber washer to try to seal better, which seems to be working. The solids digester is fed by a 75 GPH fountain pump, and an air stone sits in the part of the digester outside the cone. So far so good, it is fun to watch stuff try to come out the cone. It's very simple - the cone is kind of tilted because the cone is squished against the outlet fitting. I couldn't think of a simple way to seal a pipe going out the side on the cone angle, so I just tilted it to touch the outside of the trash can.

Oh, while I was constructing this, the hose feeding the air lift experiment fell out and drained half the aquarium! It could have been a disaster for the fish!! (See pic)

Beauty:

I think with the sunlight coming in the front house windows in the morning now that I will move the setup so the plants sit in the window in a shallow flooded tray. I may attempt to clean the 30 gallon tank downstairs for this system, and allow larger planters to be set in the tray. The flow would be from FT to pump to solids digester to lagoon (tray) to biofilter. This is the same basic setup I'm planning for outside this year.

I am glad to be using a little pump now, because the air lift was pretty weak, and solids were not being circulated out of the tank very well. I expect things to get clearer soon. I still need to up the plants for this system as the water is very yellow.

Link above was messed up, here's a picture of the aerated sludge digester:

http://www.environcorp.com/img/ais/aisce2.jpg

BTW I keep calling it aerated sludge but the correct term is activated sludge.

Regarding the air bubble siphoning effect, I bet this could be used to make a tunable standpipe siphon, with no cover. Maybe you could tune the siphon with an air valve.

It's AP Weekend! Woo hoo!

I hope to make a solids digester out of a trash can, and make and cover one or more lagoons (to set planters in) using cold frames. I may make a biofilter using a trash can and some polyester batting too, maybe. I still have lots of ammonia leftover from the basement system and will get things cycling with that. Until I get something else for a biofilter I will be keeping the 180 gallon gravel tub going. After the weather warms more the plan is to make more growing area using troughs and/or beds.

OK I'm sunburned and tired, dropped about $400 for AP supplies yesterday. Got a 700 GPH pump from Lowe's, an air pump from Petsmart (they didn't have the largest one that I wanted, wait I just realized I can swap out the one I have indoors which is the largest Top Fin one with the new one which is one size down from that), some lumber, a lot of plumbing fittings, 4 large planters, 10 medium planters, 8 white buckets from Walmart, 8 bags of charcoal.

Today I leveled out the corner area, dug in the 110 gallon tub as a sump, put together the solids digester (but I need to re-do the cone, too narrow), and tried that out. New pump really flows, probably as much as the old sump pump did. I may have to split the flow on it. The trash can overflows a bit (through holes for the handle etc.) because I put the outlet as high as possible. I plan to re-do the cone using two pieces of PVC instead of one, because one is not wide enough.

The important thing today is that I now know what I am going to do. The 110 gallon tub can be used as a DWC floating raft area, or biofilter, and/or to soak the planters in. I am going to make a frame for the 90 gallon mortar tub and use that as a lagoon to soak the planters. Both will get cold frames around them. I got 2x2s and a few packages of Winter window plastic to make the cold frames. I was going to use construction plastic but that is really opaque and I am curious about the WInterizing plastic. I got the outdoor kind so it may hold up OK.

Pictures tomorrow, the weather has gotten cold and it will be raining tomorrow probably.

Got cold again today (35F/1C) so calling it a day and enjoying the rest of President's Day.

Made another trip to Lowe's and got more needed fittings, I sure don't remember the PVC flashing being $60 a roll! Thinking about alternatives for re-making the settling cone.

Finished hooking up plumbing, but can't keep it running until I change the height in the trash can, or plug the holes at the top that are leaking. Thinking about using a sturdier trash can, one of the gray Rubbermaid ones instead of this one when I re-do the cone.

First, pictures of the Rendezvous plants as of yesterday. The basil plants are drooping, maybe because they are getting too dry, or because the window is too cold. The leaves are crinkly, I am going to see about buffering the pH as it has never been adjusted and nutrients may be getting locked out there. One is in the system now so that may show if it is lack of water. Stuck part of a budding potato in one of the underperforming planters today, we'll see where that goes. Two tall skinny plants in the big window are green bean plants. The sage next to the poinsettia is doing really well now.

Outdoor stuff

The rectangular mortar tub will be going against the back wall where it is cleared. I expect cold frames could continue around the corner and in against the nook wall in L sections.

Had a think in the bathtub, next thing to try is to measure the existing trash can and one of the Rubbermaid Brute cans, the thought there is to turn the existing one upside down inside the larger Brute. The sides of the smaller can would form a "cone" at the edges between the two cans rather than in the center.

Speaking of Hungarian weather, this is what things looked like this week. Temps 5F/-15C

ATM things are trying to blow away wind gusts to 43MPH/70KPH, it's a lot warmer though.

Oh yeah, that looks familiar

Youve been busy Dave - The snow makes your Mazda3 look angry!