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Timed siphon valve - automatically alternating between constant flood and flood & drain

Am I crazy or is this a crazy good idea?  :D

I've been thinking of the many benefits to a constant-flood setup, but I also like flood & drain with a siphon.  My crazy idea is to use solenoid valves on a timer, connected to the top of the siphon, to break the siphon whenever I want.  Instead of passing water through the valve, I'd just let air go through.

Some people, myself included, have cycled between F&D and C-F by opening the cap off the top of their siphon.  With a timed solenoid we could control this automatically!

All you need to do is open and close a small air hole to either allow the siphon to function (F&D) or to run constantly overflowing (C-F).

This setup would allow us to run C-F during the heat of the day to minimize evaporation and heat gain and then switch to F&D at night to maximize oxygen and aerobic bacterial digestion.  In the winter this could be reversed, running F&D by day to pick up heat stored (in a GH) and C-F at night to minimize heat loss.

While keeping the pump on constantly does not conserve electricity at night, it has been known to increase the life of the pump.  It's also helpful to maintain flow through the fish tank which is why I've never really been a fan of putting the pump on a timer.

Am I missing something obvious here or could this be a really great and useful idea?!?

Now I just have to rig up a test model....

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in my excitement I forgot about TC's comment on these valves needing a minimum amount of pressure to activate.  I also realized that the opening is probably pretty small (?) and very likely to clog quickly with solids.  Whereas my approach of trying to modulate the air flow instead of the water would avoid these issues altogether.

Joe, these valves usually require a certain amount of differential pressure to operate properly and a valve controlling if a siphon works or a valve letting a grow bed gravity drain is going to have almost no differential pressure and so even when the controller says the valve is open, the spring and diaphram will keep it closed at such low pressures and they will probably not work for the purpose.  I have some experience trying to get automated valves to work at low pressures.

Averan,  I wonder if some sort of actuator would be able to dip the breather tube into the water or lit it out depending on the timer?  Now I still think some sort of pinch valve is probably the way to go but I'm shocked I haven't been able to find one for under $30, I could swear a few years ago I found plenty cheap but then again I was looking large valves then so didn't pay much attention to the small pinch valves.  Perhaps if you do a youtube search of Robs videos and find his video of the motorized sequencing valve he made, that might give you some ideas since his sequencing valve was designed for use on small tubing.  Granted, it would involve a bit more DIY construction and a controller for the little stepper motor but it will probably get you thinking.

Evidence supporting my exploration into the benefits of controlling/bypassing siphons to alternate between F&D (flood & drain) and CF (constant flood) states in media beds:

[taken from http://www.growstone.com/products/faq/]

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7. Do Growstones facilitate grower crop management and plant steer ability? 
Yes. Steer ability is a measure of easiness of maintaining the crop in balance between vegetative and reproductive growth. The high aeration associated with medium water holding capacity makes it very easy to steer the plant and reach this balance. This is accomplished by controlling root zone moisture content. With Growstones, the root zone can be as dry or as moist as the grower needs it to be, and the desired root moisture content is achieved quickly.

Growstones easy and quick control of moisture content, facilitates steering plants via irrigation scheduling: wetter root conditions from increased irrigation frequency lead to more vegetative plant growth; reduced irrigation frequency leads to drier conditions and promotes reproductive growth (plant tends to set more flowers and develop fruits faster). Plants grown in Growstones respond fast to changes in irrigation scheduling and environmental strategies. Growstones drier nature also helps suppress root diseases such as Pythium, facilitating crop management compared to substrates with high water holding capacity.

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I know I've been told to KISS and just put the pump on a timer, but there are many benefits to letting the pump run continuously, particularly in hybrid systems.  And if the right piece of equipment existed to automate control over bypassing siphons it would make a lot of things much more simple.  You could even have different beds setup differently to favor certain crops.

But you can acheive all that you wish Averan.... without siphons... just with a normal overflow standpipe... and a timer...

 

Set the timer to run for the period you want as constant flood of the grow bed... then when the the timed period is off... the beds will drain via the small holes in the bottom of the standpipe...

 

You can then set the timer to "interval" flodding for as long as required.... and swich back to constant flood whenever required...

 

I just don't see why it needs to be any more complicated than that... to acheive your desired outcome(s)...
 
Averan said:

 

I know I've been told to KISS and just put the pump on a timer, but there are many benefits to letting the pump run continuously, particularly in hybrid systems.  And if the right piece of equipment existed to automate control over bypassing siphons it would make a lot of things much more simple.  You could even have different beds setup differently to favor certain crops.

hybrid systems + trout

im not sure there is really that much to gain from all that control. when it comes to keeping up with an ap system, you want as few variables to keep up with as possible.

i agree that a standpipe and timer work very well.

here is a pic of a perforated stand pipe, works great. the pump runs for 10 mins every 30 mins. if there is a problem, the stand pipe will just overflow. ...not the grow bed.

 

 

If wanting to have the constant pumping for aeration for trout, simply have two pumps, one constant for the aeration and the second would be on the timer for the beds.

not for aeration, for exercise/health of the fish and removal of solids.

i'd have to come up with a very different plumbing setup in order to run 2 pumps that way, unless the fish pump is just circulating water around within the tank.  in my designs, the fish tank always overflows into a media bed to maximize bio-filtration.

also, i've heard that pump startups require spikes of electricity that don't play well with solar applications.  having a solution in place like the one i suggest would help.  on the other hand, one may argue that the extra energy usage of constantly running a pump would put a significant strain on a solar power supply.  

thanks to everyone for their input.  always good to look at a problem from as many angles as possible.

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