Backyard Aquaponics
A place to discuss aquaponics

OK. Been looking at a few systems and their parts and functions and have an idea I'd like to bounce off you folk.

Please correct me if I'm wrong I'm F&D virgin.

The water level in the beds gets to a certain height (? cm's below the top of the medium). Upon reaching this height, it all empties. Then refills...

If this is correct I think you may be able to eliminate the surface grid of piping in growbeds.

I'm thinking - That filling the bed is the desired end result. Water from the top can increase algae. Water through drip and flow holes get clogged.

So why not have one large hose on slow flow directly filling the bed.

Say you have a 1.2 x 2.4 metre growbed. Your water would likely be distributed with over 10 metres and many fittings of 25mm pvc at 300 mm intervals.

How about one 35 mm inlet that inserts in a 65 mm or larger pipe inserted in the bed much like Joels drain. This drilled to halfway to the 'high water mark' with maximum outlets possible. It can be spun if the 35mm pipe in is set loosely, removing invasive roots. Plant wisely around it This area may be too large, but I think 1 65 mm inlet per 1 m2 would provide adequate nutrient spread.

The bed gets filled and drained much the same as it would normally however solids will be concentrated more at the bottom. The fact that worms just 'arrive' in outdoor systems bodes well for this being workable. They like it down there, so put some in.

Plants fruiting heavily will have a sturdier food source to tap into while surface feeders will be replenished constantly by the water.

Would it work or am I mad

Is there such a thing as a pre-virgin?? - that would be me in flood and drain...
concept sounds fine... but is it really flooding that we are after, seem to think that its more a adding of water, letting it drain, return it to pond, start again...

I think I have the hang of what your sayin there AA... I think....

Next time I do a large flood and drain system I think I'll be using a lot less pipe and fittings than what I have in the original system. For large round beds like I have at the moment I would probably put just a + across the bed with maybe 10mm holes drilled into the base..

I do like the idea of spreading the fish poo out over a fair area rather than keeping it to localised... I feel that a surface grid is good for spreading the poo more evenly, and I have never had a problem with algae and blockages so long as you open up the pipework and check it between crops. I like the idea though, it's inventive and could work alright.

Interesting.
As I get closer to actually putting the system together, I have a few questions that I would love an answer to if possible. You have just answered the first one. I was wondering if the flood and drain needed such an extensive grid

With AA's suggested approach, would seeds still germinate as easily?

I think so. If the water comes to a certain level regardless of how it's put there it should be the same conditions for seed.

Seed would not like to be directly by a water inlet so it shouldn't matter.

I'm not saying it wil work I just wonder if it will. I can't see why not but someone else may see something glaringly obvious to them. That would be great saving time and headaches for Flood and Drainers.

EB - I've read and read. How does your drain work? I'm under the impression you flood your beds meaning they are mostly full of water at times. How does the drain know when to kick in and empty the bed?

Yep, water will still come up to whatever level in the gravel so aqny seeds that have dropped down into the gravel will germinate.

It's all in the standpipe AA, check the picture in the book of the standpipe, or it's also on the DVD... The water is always draining from the beds through the two small holes in the bottom of the standpipe. The beds fill quickly from the pump, then take about an hour to drain out slowly through the holes..

Ahhhh, the penny finally drops. I envisaged it filled and then like pulling the plug and whoosh - it's empty! rofl!

And for the life of me couldn't figure out the moving part... very amused now. It's because I've seen those syphon things for ebb and flow before I saw your system and thought you had a larger variant.

Had me flummoxed!

With timing your flood and drain periods etc - what is the parameters for - max submersion time and max drained time. I imagine it's flexible but a ballpark of what I could play with.

I think a continuous flow pump could even have the (this) 'cheap version' of plumbed growbed through having a larger volume water discharge via a ------ (what is the name of the things on the barrel system) ------- than the volume of water in. It fills slowly with highly oxygenated water plumbed in via a venturi, then is removed at 3 times the rate, of course, the flow continues. So roughly twice the time to empty factoring in the water arriving as 'draining' commences.

Must go read blue barrels again, or find that plumbed thingy....

Alright you've lost me know with that last bit.....

My flood and drain stays pretty constant at an hour between flood cycles, it constantly floods and drains so there is always a little water in the bottom of the growbeds even at the dryest point of a cycle.

No problems I lost meself! Basically, I think a continuous flow could be jury rigged to flood and drain. Why? - to save on plumbing the top of the beds. Why continuous then and not just flood and drain? A good 24/7 pump is very hard to kill. And I will need a less powerful pump.

Done properly I think a mini sytem can be designed like my kitchen herb garden (it's coming along slowly..) with plumbing so minimal you barely see it.

That piece on your barrels, the ebb and flow bit. What is it's name and where was that link I've lost it.

That is the missing link you see, the bit that eludes my thinking.

AA a continuous flow flood and drain system could just use one of the auto siphon loops. It will work fine as long as water in is slower than water out when the siphon initiates.

EB, brain wave, raise your beds higher (yeh right he says ) or extend the end of the siphon further down before it goes into the horizontal drain pipe. I think this will fix any leaky siphon issues.

This is my thinking, i bet that the draion rates is much faster than the fill rate as soon as the siphon initiates. Then, as the head pressure drops (due to the water level in the half barrel dropiing) the siphon flow will also slow. If it reaches the same flow rate as the water in then you will have a permanantly leaking siphon. by extending the siphon tube lower there will be more "relative" head pressure. Will move this over to the siphon page later.

You are talking about the syphon. I assume what you are getting at is having the bed fill slowly using a low capacity pump, but then syphon quickly via syphon action once it receives the desired height. The pump continues to pump, but is slower than the syphon so will empty to the point at which the syphon stops.

I have been thinking of trying the same thing AA as my current pond pump which I use 24/7 only pumps 2000lpm at 0 head, not sure what at the head I will be using with my big bed. My only concern is whether i can get the syphon to work well.

EB, how did you go with the ball thing. Did u end up trying any of the other ways discussed?

Exactly VB.

What i was getting at with the "head" was that if the end of the siphon is a little stump just under the barrel then the flow will go down to a trickle when the water level come close to the bottom of the barrel, hence finding a balance point with the water in, and not work. What i was saying was to have the end of the siphon as low as practicable. ie biggest height difference between bottom of barrel and siphon final outlet point. (picture the snowy mountain hydro electric scheme ) This will give the best flow at low level, and hopefully still faster than the water inlet. This is why a wider shorter grow container would work better for this application than a skinnier and higher container.

Draw your design Steve - for AA's benefit

You're onto it guys. The auto siphon is exactly what I was thinking of. And getting the drain lower with the bed directly above shouldn't be too hard I just need to get my hands on a bit of pipe in daylight tomorrow make an auto siphon to play with and understand it better.