Backyard Aquaponics
A place to discuss aquaponics

Hi Dave,

Hmmm...
3 valves @ $15 + 1 pump @$20 + 1 irrigation controller @ $75 + a 3-way manifold @ $10 = $120
-OR-
3 pumps @ $20 + some kinda 3-way electrical switching kinda thingie...

What kind of device to turn the pumps on and off did you have in mind? Technically I could use 3 light timers, but is there anything that would do it all in one? If I use 3 pumps and 3 light timers, I would spend about $120. So cost is all about the same, but your idea eliminates the risk of Sol valves. Anyone see any drawbacks? Any problems with cycling pumps on and off frequently? (I would be inclined to use little magdrives.)

Keep the ideas coming...this is fun. I probably shouldn't mention this, but one 50-gal Rubbermaid tank just exactly fits in the backseat of my car. It followed me home, honest. It won't eat much, and it's only one, Mom. Can I keep it? (It was on sale!)

--Janet.

Ah! Found a nice 24-on 24-off timer for $13. So the light-timer method is cheaper by $21 if I can deal with controlling the time in 30 minute increments.

Janet...my internet at work went down today I was prepared to discuss this. There are a few ways to cycle your system and there is some debate on which is most efficient. IMHO the simpler the better. The more pumps and valves you cycle the more it cost to grow stuff. Resistance from closed sol valves means huge loss of energy and the harder your pump works and there is extreme energy loss when valve is closed, line is pressurized, pump is running, but no water is moving. Use gravity whenever possible. Use natural light and heat whenever possible. Consolidate beds (and plumbing) wherever possible. One pump could cycle the entire system.

One pump could cycle the system, or 10 pumps could cycle the system, for the same $ depending on the design. The first pumps I bought were $100 each and too big for my system at the time, the more recent smaller one was $40. I am on the downward curve there.

Janet, I am also thinking about the next next big one (because I am not able to actually work on the immediate next one right now!), and the scaleability and redundancy of multiple small pumps is intriguing to me.

It is similar to certain designs in computer science, like RAID disk drives arrays - you gang up multiple cheap drives to make one big and fast "drive", or say buying a sackful of relatively small and cheap Mac Minis to make an inexpensive render farm. These ways of doing things can be much more cost effective than buying the fastest disk available at the time or the biggest computer available at the time. Or in RISC computing, where the theory is that you use more numbers of simple instructions rather than less number of big instructions. It's a similar concept. It's fun to think about this stuff!

Edit: Another example - buying two cheap 17" LCD displays instead of one really expensive 30" LCD display. The architects who use our CAD program do this often.

BTW, what I'm thinking about is an "overflow" system inspired by how MF has organized his. I am thinking about a main tank about 500 gallons, continuous pump (with UPS backup) in the tank with venturi for circulation and aeration, overflow from main tank goes to multiple 50 gallon sump barrels, each with a small continuous pump (always running), to a 100 gallon bed (50% medium to water ratio), draining back to the tank with siphons so they are flood and drain. Beds (and pumps) could be taken online or offline as the fish load ramps up or down. At the start of the season you might only have one grow bed running and at the end you would have maybe 4 or 6. Each sump barrel/grow bed/siphon "module" added would add water and buffering capacity (i.e. stability), so if you had the initial 500 gallons and 6 grow beds going your water volume would be up to 800 gallons.

DD,
I don't understand why you need the sump barrels, but otherwise, I like the idea of small redundant simple systems. Us computer nerds gotta stick together!! Were you planning on having so many units that you don't want 20 pumps in your fish tank? Let me see if I can put my drawing up here....this is what I am thinking of doing now: One tank, 3 small pumps, 3 light timers to stagger filling, no Sol valves, and auto-siphons on the grow beds. And I really can't expand past 3 beds. No more space in the sunroom.

--Janet.

DD,
In fact, as I think about it, multiple sumps scare me. Let's say you have 3 sumps filling from overflow from the tank. (The overflow is exactly equal to the sum of the output from the three pumps.) Unless you divide the overflow -exactly- in thirds, wouldn't the shorted sump eventually run dry? And the sump that gets the largest share overflow? I think it would be better to cluster the pumps in one sump--if you decide to keep a sump per my question above.

--Janet.

Hi Janet:
If the sumps are joined by a balance tube they will all be at the same level. With evaporation you might get to the point where pumps start running dry, and I'm still thinking about that. One way might be to have an extra reserve/overflow barrel that somehow automatically adds its water to the system when things are running and fills up when all the pumps are turned off. It would be like say four grow beds sumps full and the reserve sump like half full, if there was a power failure.
For the reserve to automatically empty when the power comes back on, I was thinking about having a venturi line inlet in that barrel, so that it would draw water into the system until it ran dry then it would be aerating from then on.

The reason for the sumps is that if (when) the power goes out then the water can drain down into them and it is not a big deal to get things back up when the power comes on again. The fish tank has a constant amount of water in it, and so the sump/grow bed pair trade a contstant amount of water between them.
In my (first) system, the water level just fell when the pump came on. This wasn't a big deal because I was only losing about 25 or 30 gallons out of 100. But when you need more grow bed volume (like EB recommends 2:1 gravel to water when there are lots of fish) that amount of drop is unacceptable - the tank would be empty! - and you need to have more capacity through sumps of some kind, or stagger the grow bed filling like in your sketch.
Your sketch would work fine I think.

DD,
Ahhhh, the light goes on! So your multiple sumps actually function as one if they are joined up. And I had to think about it, but now I understand how the sump keeps the tank level constant. I shall have to contemplate things some more, but I'm glad to hear that you think my current design would work.

--Janet.

Hi janet i like the idea Questian where did you get the rare yellow tialpa

Oh, those "Rare Yellow Tilapia"...yes sir, very special, those. They leap right into the frying pan if you whistle just so: two longs and a short.



Janet.

Found this indirectly from a post on DIGG today; it's a relay board you can hook up to the printer port and control with software - if you have the inclination it would be fun to experiment with.

http://www.electronickits.com/kit/compl ... ck1601.htm

I have personally built one parallel port relay outcircuit using some circuits and software found on the net. I use it to control my machine in the production line.

There can be only a max of 8 output from the parallel port unless you were to multiplex the design. The device uses the parallel port / printer of the pc. There are 8 digital output from the parallel port , I only utilize 4 digital output(i only need to control 4 device)

The output from the parallel port is connected to a transistor circuit that turns on a relay circuit. The relay circuit can then be use to power up whatever external device that you want to control (on / off). The transistor circuit is needed to protect the pc parallel port and also because the current output of the parallel port is not high enough to energize the relay.

You will need to find the suitable relay for the power rating of your device, as there are a lot of different type of relays.
The software can then be use to control the electrical device through the pc parallel port. I got the circuit of my device from the internet.

http://ourworld.compuserve.com/homepage ... /page6.htm

http://www.epanorama.net/circuits/parallel_output.html
- good explaination with software

electronic Kits
http://www.electronickits.com/kit/compl ... ck1601.htm

below is a circuit i use to connect the PC parallel port to energize the relay coil.