Ebb 'n' Flow Methods With Pressurized Delivery

[Sean Gunn]

I've been following Bright Agrotech videos and I like his advice. It seems to be extremely well-researched and also backed by many years of experience. He recommends running systems under pressure, possibly using timers.

So, I know of 3 ways ebb 'n flow, or flood and drain can be done using pressure:

1) Overwhelm a small/slow drain with a pump running periodically on a timer.

2) Bell Siphon that overwhelms the inflow with a large drain, no timer necessary.

3) Flout that overwhelms the inflow with a large drain, no timer necessary.

Are these descriptions correct?

Is there another common and/or easy scheme to implement ebb 'n' flow with pressurized delivery (and/or timers)?

Do most people run their siphon or flout systems 24/7 or do they turn pumps off overnight?

Ideally, I'd like to run the pump(s) continuously for longevity but I suppose it is not necessary.

I am considering flout based design at the moment but I want to make sure I understand all the common/good options.

[Jonathan Kadish NYC AA Chair]

Check out the EZ T Siphon for flood and drain grow beds: https://youtu.be/78RSdbhBq5A

[George]

I run #1, usually both day and night but presently daytime only due to low temps.

[Sean Gunn]

Thanks! These are just the kinds of tips I'm looking for.

I like the simple T siphon very much! Do you know if it scales to larger diameter pipe? It seems reasonable that it would scale but I've not yet built any sipons, and I am not educated enough in physics to fully understand all the dynamics.

I'm considering a design that puts the drain control in its own tiny box, connected low in the bed that can have a grate or screen that is easy to remove and clean as periodic maintenance, thereby protecting my siphon/flout/whatever from roots, media, and system solids. That way I can just clean and protect an easy to remove part instead of the flout or siphon. Does this make any sense? Have any merit?

I was informed on another forum that I need to run continuously for aquaponics if I have no other form of aeration--which seems obvious, but good to keep in mind in design.

[Jonathan Kadish NYC AA Chair]

Yes that's why we flood and drain constantly- for aeration. And yes the T Siphon will scale up although you would need to increase all the pipe sizes accordingly.

[Jonathan Kadish NYC AA Chair]

Also try not to reinvent the wheel when you are first starting out, you have a lot to learn and making a system more complicated will only cause you to tear it up, break it down and start over. I know this from experience trying to do the same. If you love problem solving then by all means go rogue, if you want to grow plants use the tried and tested. You'll find most people here just want to share what works, we all build on each others work.

[Glenn]

There is also to consider, indexing or programmed valves. Where flow is routed to and/or from separate beds or zones at timed intervals, with over flow piping to prevent overwhelming flood cycles. This in my opinion is the most complicated with more moving parts, but perhaps a little more accurate where precise cycles/times of water delivery is desired. 

[George]

I use an indexing valve to flood and drain six beds with no sump, no siphons.  The valve is indexed by water pressure when the timer sends power to the pump.  Each bed has a separate input pipe from the valve.  I consider it less complicated than six siphons with a sump.  Two things can cause the valve to fail, low pressure from pump and debris causing clogging (will also cause siphon system to fail).  The valve I use, sold by Aquaponic Lynx, works with relatively low pressure.  

Glenn said:

There is also to consider, indexing or programmed valves. 

[Sean Gunn]

I do have some experience growing plants in soil and with ebb n flow. I would be learning a lot of new things but not everything. I'm pretty handy and like to put my time in researching, planning and implementing things. I think whatever grow beds I build will work if I plan well. I can build one media bed and test my design before building any more.

What I am most worried about is getting the aquaculture side of things right if I go aquaponic instead of hydro. I know from my hydro experience that young plants can be finicky in such systems. I suspect it is easy to under or over feed plants until you figure it all out. I hope to grow some fruiting plants eventually like tomatoes, eggplants, and strawberries. Then, there is also the health of the fish to consider.

I'll definitely be checking out the programmed valves. In fact, I was looking for valves on timers just yesterday. Maybe these Aquaponics Lynx valves are just the thing! Valves on timers seem like an obvious solution to ebb 'n' flow with constant inflow but I hadn't found anything yet.

Thanks!

[Sean Gunn]

I see the valves for controlling flow to the beds as mentioned by George but can you point me to a resource for valves to control flow from the beds? I assume by this you mean the "programmed" valves.

As for the indexed valves, each bed would have a slow drain back to either the sump or aquaculture tank, and only one bed would be topped up by inflow at any given time, correct?

There are many more options than I ever expected, thanks!

Glenn said:

There is also to consider, indexing or programmed valves. Where flow is routed to and/or from separate beds or zones at timed intervals, with over flow piping to prevent overwhelming flood cycles.

[George]

Correct, although you have the option of flooding multiple beds, if, for example, you wish to partially drain the tank to harvest fish.

Sean Gunn said:

As for the indexed valves, each bed would have a slow drain back to either the sump or aquaculture tank, and only one bed would be topped up by inflow at any given time, correct?

[Sean Gunn]

The only programmed valves I find for PVC are $4-500. Is this all that is available?

[Glenn]

You might check your garden supply/hardware store like Home Depot for "Melner 4-Zone Watering System"  It should be known that a lot of low cost home watering system valves have copper (or worse) internal parts so should be avoided for the sake of fish and our favorite microbes. And there are all kinds of valves, some with very restrictive ports that can plug easier than full port ball valves and some gate valves. Another good reason to use swirl filters and to get those non dissolved solids managed.

There are other types of sequencing systems too. Like non electric even that uses air, gravity, and mechanical  timers etc.

If you are in an area that has some high volume industry, you can probably find a supplier like rain for rent that can help advise you on what's available to suit Aquaculture in general.