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hello, everyone.  I have bought IBC tanks.  I cut them where the top and the bottom will make grow beds.  each one is 20inches high.  I really hate to cut them down to 12.  Any reason, that we do NOT make the GB deeper than 12.  Would not that help in growing plants with big and long roots?  Thanks

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Absolutely, positively no reason to cut them to 12". 20" would just give you MORE bio-filtration and mechanical filtration within the SAME foot print.

If you will pardon the diatribe:

Somewhere, at some point, a scientist (or grad student) said "12 inches seems like a pretty good depth for an AP grow bed"...and, as often happens, with things that trickle down to us masses...that became transformed into a "standard" written in AP stone "Thou grow bed shall be 12", neither more than 12", nor less than 12"...It's just a convenient number that satisfies some physiological needs of the AP eco-system, and happens to be easy to calculate certain ratios...square footage, to cubic feet to lbs. of bio-mass etc...etc...etc...

Much the same way that the "ideal" timing sequence for a pumps flood and drain cycle is 15 minutes on/45 minutes off. It has nothing to do with the 'optimal' working parameters based on the biological demands of the system, or the physical abiotic environment in which the system operates (or efficacy)...but rather that the cheap, readily available, Chinese made mechanical timers are produced which have on/off intervals of 15 minute increments. A gear is circle...a complete circle has 360 degrees...there are 24 hours in a day (our mechanical time pieces [clocks] are also expressed within the syntax of a circle...24 (hours) multiplied by 15 (minutes) conveniently gives us 360 degrees)...thus completing the circle (gear) with 96 easy to operate pins...simple and well suited for generic mass production...

It has nothing to do with what is actually "optimal" for the workings of a given system, operating in a given environment. It just 'happens to be convenient', and 'happens to work' OK in most's far from "the best" or "the only way" to do things.


Now changing subjects on you.  I initially used syphons, they are tempramental.  I looked for other options, I find timer, standpipe and a drain pipe next to it.  I am sold on the idea, but I have not bought the timer yet.  I am not sure if 15 minutes would do the trick for me.  I am not happy about the increments in 15 and not 1.  What do you suggest/use for GB water drainage?

Thanks a lot!


15 minutes on/45 minutes off, would likely 'do the trick' for you.(or increments of 15min).

The "ideal" pumping sequence would be one that does not allow the grow bed to completely dry out (this will be dependent upon what media you are using, whether you live in Dubai or the Pacific Northwest (temps and humidity...time of year)...your stocking density, the volume of your fish tank, and the cost of electricity in your area...Again, for "most purposes" 15/45 is perfectly fine (just not "optimum", or "ideal").

I like a good repeat cycle time like the Omron H3CR to give you a nice wide range of options to play with (time settings range from 0.05 seconds to 300 hours).

It's a $70-$100 investment who's capabilities are probably over-kill for most folks, but will allow the inquisitive the freedom to explore and play (if that's something they desire) with pumping sequences (and system ratios).

Particularly handy (in my experiences) if you have multiple grow beds and peripheral sub-systems (and need the pump to operate items like sequencing valves)...

There are of course other quality repeat cycle timers available (both digital and electro-mechanical), but I'm a sucker for anything analog, round and Japanese made 

Yes, siphons can sometimes be rather finicky...dependent on flow rates...

Here's a timer I use at a client(s) build...multiple grow beds and sub systems...sequencing valves...

They just want "shit to work", not play with precise optimal values. So, it works fine for that purpose. It's not my favorite timer for anything requiring precision dialing, but is easy to use and there is no wiring required (unlike with the Omron)...and has been reliable (and cheap) thus far.


This is question for George,

you mentioned that you have one pump, one timer, one index valve, and six GB.  How big is your sumb tank?  if all the GB's are draining at the same time, you must have a ST big enough to accomodate water from 6 GB?



thank you very much for your valuable feed back.  I really appreciate the "support" I am getting from you regarding "my thoughts".  It is good to know that someone else shares the same convictions.  Also, I posted a question about the practicality of using one timer, one pump and six GB's, I do not see it possible to have a sumb tanks big enough for all that water coming down during the "off" cycle which will be for all the GB's.  Your thoughts and support are really appreciated.



That's the reason for the sequencing valve and repeat cycle timer. It allows you to fill and drain the beds individually in sequence, escaping the need for a gargantuan sump tank. It's the whole 'beauty' of it.

little did I know!! is the index valve the same as the sequencing vavle?  How does it work?  If I plan to have 6 GB's and I want to start with only two, can it accomodate for expandability?  I love it.  I am almost there with my $60 timer that your recommened, stand pipe, drain pipe!! no more syphon.  Please advice?



Yes, they are the same thing.

Yes, you can purchase a 6 way index valve and install a 2 way cam. Then when you want to expand, replace the 2 way cam with a 6 way (or 3 way cam, 4 way or whatever).

There are no electrical parts, and not much to break. The valve works by water pressure (flow). Inside there is a stem disk assembly and a simple cam. When your pump turns, the water flow presses the rubber disk against the bottom of the valves housing where the zone outlets are, thereby 'sealing the disk assembly'. The disk has one cut out that allows water to pass through it to flood your bed.

When the timer turns your pump off, and there is no water pressure (flow) anymore, the disk assembly (via a spring mechanism inside the stem) pushes upwards into it's natural 'open' position. As it slides upward over the cam, it turns to the next irrigation zone position...when the timer kicks the pump back on...the cycle repeats itself...

Some of mine have been running for years with no issues.

You can use them to flood 10 gallon beds or 10,000 gallon beds, and anything in between (it would just be a matter of setting the timer to your needed 'on cycle'.

You set the timers 'off cycle' to however long you need to drain the bed before the next on starts to fill. This means your sump is only receiving water from one bed at a time, so you don't need a sump to handle 6 grow beds draining at once.

Don't buy the regular indexing valves on the net or the Big Box stores as you will need a pretty big pump to operate them. The disk assembly needs to be modified for AP. I have about a dozen or so such AP modified valves sitting in my shop.Iif you are interested PM me. (I don't care who you buy them from, just letting you know that I have AP modified ones available if your interested).

no sump.  the beds flood one at a time and then drain completely before the next bed floods.

Moe said:


This is question for George,

you mentioned that you have one pump, one timer, one index valve, and six GB.  How big is your sumb tank?  if all the GB's are draining at the same time, you must have a ST big enough to accomodate water from 6 GB?



Thank you for your suppot.  question: What method od drain do you use?  I have a bit of a concern, I do not know if it is valid.  Right now, as you know, I have 1/2 IBC tanks for GB.  I have not filled them with media yet, I am in the stand construction phase.  This is my second system, so I have a bit of experience.  in the past I drained using a syphon, and that was the only thing that kept failing.  I want ot get rid of this point of failure.  now back to my question, if I use the plan that you are suggestion, to "on" cycle enough to fill one GB and "off" enough for it to drain, suppose the on is 20m and the off is 30.  That means every GB needs 50 minutes.  This means that if I have two GB, one of them will be "waiting" for water for 50 minutes.  if I have 3 GB, that means each one will wait his turn for 50+50minutes and so on?  would it be a waste to have beds wait this long?  your thoughts?  Thanks



What method of draining you use, how do you not have a sumb?  where do you drain to?




What happened, how come no one is replying to my questions.

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