Backyard Aquaponics
A place to discuss aquaponics

Guys

Im seeing "Sequencing valve" pop up more and more these days. For us that may not have a great understanding of it (the whole process), can those who have it explain so its in 1 place - please? Im just planning an upgrade with up to 20 barrels (40 x 1/2) so it would be good to have some info incase its an option for myself & its in the 1 area.

I understand it in principal (but not totally for AP). Water goes into the Sequencing valve and to its destination. Water supply interrupted and the internals of the valve move it to the next outlet (mechanically or electronically within) so when the supply is established, it goes to the new destination and so on (had a mechanical one of these for some pop up sprinklers 10 years ago).

I also read this is for a timed method, the "normal" 15 mins on/45 off (as apposed to 24/7 flood and drain Siphon method). Does anyone have any further details on this and Pro's and Cons? My thoughts are from reading:

Pro
Less sump sized required due to not having to fill all the beds up at the same time


Con
Constant turning on and off on the pump may degrade its life
Quite a major point of failure potential, unit & associated piping


Thanks in advance

Well in principle, it distribute water similar to that of the irrigation/reticulation indexing/sequencing valves, except that I believe the AP ones may be slightly modified. RupertofOz sells them. PM him.

The growbeds drains are connected back to the tanks (fish/sump) as per normal. In fact, depending on your system size, etc, having the valve may eliminate the need for the sump. One of the reason why you need a sump is because of the amount of water required to fill the growbeds and if it is taken out of the fish tank, then the water level would have dropped drastically. But with the indexing valve this may not be the case since less growbeds are filled each time. But of course they are other reasons you may need a sump for.

If you are thinking of going indexing valve (at least the mechanical type), you will need to interrupt flow and a cheap and less complex way of doing it is to stop the pump. The cheap 15 mins interval timer will be a low cost way to implement this. Hence the 15/45mins flood and drain duration is actually because of using this type of timer.

I have started and stopped my pump on timer for over a year now, and I think other people have for over a few years. I think they do last for a while. In fact, I believe stopping the pump helps with "back-washing" the pump (of crap that just stuck to the strainer).

All your points are correct.

They (indexing valves) are another point of failure, however it is not a catastrophic point of failure. Providing all the joints are glued correctly, the worst that can happen is it gets stuck sending water to one set of beds only. Even this is pretty unusuall, because as Ivan says, the valve gets backwashed with the water returning to the tank when the pump turns off, this forces the valve to lift, and it will be able to rotate to the next position on pump startup.

Pumps are not usually a weak link either, all the decent ones are pretty reliable, especially the tornado submersible type - I cant recall anyone having a failure of a name brand one yet.

The weak link in any system that uses mechanical timers is the timer itself. Sometimes you get one that will last for a year or two, and then you get a run of bad ones that get stuck after a day. If it gets stuck in the 'on' position that is fine, but if it gets stuck in the 'off' position, well the results are pretty usually bad.

Cheers Guys

In that case, if the GB needs to go back into the FT - it wouldn't be CHOP as you would need the GB's to be higher to allow the water to run back into the FT (with the "NO SUMP option")?

Whats the benefit then - compared to a normal 24/7 bell siphon system?

Im chattin to Rup also

Theres a lot of different ways to set up a system. Solids lifting or a pump in the FT. If you are going to run 40 1/2 barrels you could use a 4 port or 8 port and fill 5 or 10 gb's at a time. If you just use a standpipe with a drain hole then you would have water returning to you FT all the time. If a standpipe hole gets blocked it would not take a lot of water away from the ft.

I use an 8 port to cycle 12 gb's.

Cheers -however this means the FT needs to be lower then - I think

In my solution, I want my FT in the shed (3 x 500 litre bins) then GBs outside in a greenhouse. They would be quite high to be able to drain back to FT

Hence it depends on your setup as I mentioned earlier, if you prefer not to have the growbeds too high, then you need to have a sump tank lower than the growbeds so that the growbeds can drain to the sump tank.

And then either using SLO or another pump, move the water from the fish tank to the growbeds.

Exactly how high are you talking about? It is generally not uncommon to have the growbeds above 1 metre or so off the ground. Better for the back.

Agree. Its relative to your FT height. FT height is say 0.6 m high (all on flat ground - and that's not high compared to IBC's I have) then you would need at least 400 mm for the GB @ 300MM high and then another 200 mm for outlet from GB and some fall back to FT. Conservatively, would mean you are picking at something that's potentially 1.2 metres high. I also read that water depth of 0.8 to 1 meter is advised , which is worse.

In my config, its all level. FT drains into GB which bell siphons into sump. Sump pumps up to FT. If I had the FT lower - I can see advantages

For the config I have now, is their any benefit in a valve?

I have a set up where my fish tank is about 4 feet tall, the tops of the grow beds are a fair bit lower than the water level in the fish tank. My pump runs continuous and the grow beds drain into a sump tank.

I am managing to use a gravity modified 1 1/2" indexing valve to sequentially fill 6 of my grow beds but that requires the use of a low pressure automated valve that I designed and Novaris and Jazzyplayermark helped me with controllers for it. It is possible but it does add a layer of complexity.

on another note, I also have a large on the ground grow bed that gets overflow beyond what the first six beds use, that bed has a float controlled pump in it which feeds a regular 1" six way Aquaponics Indexing valve which feeds my line of barrel grow beds growing my screen of bamboo. the water draining from those barrels flows back to my main sump tank.

So what is the benefit to a person with a simple CHIFT PIST system? Well that is a bit of a tricky answer since you need a fairly sudden gush of water to really engage the valves properly. Simply running the pump on a timer into the fish tank might not raise the water level fast enough to engage the valve properly. However, if the fish tank is high enough above the valve and you have some way to stop and start a large/strong flow of water to the valve, you can get away with a much smaller sump tank. The real challenge is the method of stopping and starting the flow to the indexing valve in a manner that will still operate the valve while not causing overflow problems for the fish tank. (I've been doing it for my system for over a year and I love it but I don't know how to tell some one else how to do it in twelve words or less.)

Now if your system already has some grow beds and a sump tank running. You might just think about adding a pump to the sump tank and using it to feed the new barrels and have them drain back to the sump tank provided the current sump tank has a little extra capacity. The barrels might not get much in the way of extra solids but I can tell you that my barrels being fed by a pump with is getting filtered water, as it is a float controlled pump in a big grow bed, are doing well enough.

I'm able to flood 3 half barrels easily through my 1" valve in under 7 minutes with a 1/3rd hp pump. I expect I could easily put 6 half barrels on an outlet if I were running a pump on a timer to feed them for longer. A larger valve would probably provide more flow faster and be able to feed more barrels at once but the larger valves only go up to 6 outlets, while the smaller valve can be gotten in an 8 outlet model which would mean 5 half barrels per outlet.

My setup also using a sequencing valve that I built myself. The pump is continuous running from the fish tank. There's a small motor on the valve that changes the index position. The beds drain into a sump which then pumps back into the fish tank.

This one has been running non-stop for about 1.5 years. It is clog proof and I haven't had to do any maintenance on it: http://www.youtube.com/watch?v=u7XGME4kdJc .

If you are going to use a sump, make sure you have level cut-off switches so if the sump pump fails, you can turn off your primary pump. I learned the hard way about this!

yup - seen your valve earlier today - really kewl

Benefits of this over std bell siphon flood and drain?

You could just split a continuous feed, and use "std bell siphon F&D," but it would be difficult to get multiple siphoned growbeds to take turns draining. The benefit is to even out the size of the "slug" of water that is lifted from the FT and/or ST at any given time.

Let's break it down a little more -
Sequenced feed, drain via holey standpipe ---> controlled amount goes out and then comes back. Then next slug goes out and comes back. And so on.
Little Sump Tank Level Change.

Split feed, bell siphons ---> alternate events of A) little water returning, low water in ST and B) LOTS of water returning at once to ST.
Potential Hyuge Sump Tank Level Change.

A "big enough" sump tank is defined as having the overhead and underhead (is that a word) to accommodate the HIGH water from all GBs being EMPTY as well as the LOW water from them all being FULL.

Simply put (about time, Rick!), a sequencer relieves you of a lot of Sump Tank Capacity, as you plan additional growbeds. And "additional growbeds" is always a good plan, isn't it?

Of course, your mileage may vary, void where prohibited, and past performance does not guarantee future results!

Rick

If you still choose the sequencing valve. the problem with turning a pump on and off is that the pump uses more power too start up, you can however and this is just another suggestion is to put a solenoid valve on the line controlled by a retic controller and put a pressure relief valve to prevent pump dead heading (relieving back into the fish tank, assisting in aeration) This is purely just another suggestion, I understand you want to avoid weak links but you also have to do what you feel right with, after all your maintaining it. it does make sense when you start getting bigger systems, but remember you need to balance your system, more GB means bigger FT. Rock on.

More than a few problems with that approach ... the solenoid valves are costly... require pressure to run that means larger, more costly inline pumps...

And they're not generally designed for "dirty" water such as the water in an AP system... which not only contains solids... but leads to bio-film buildup...

An aquaponics sequencing valve at around $100... is a hell of a lot cheaper, simpler and more reliable solution...

I've seen a picture of one install where there is a solenoid valve controlling the flow to an indexing valve so the pump could run continuous.

I don't know how well that install is functioning nor do I know how big a pump they are having to run for it since most solenoid valves require more pressure to operate and will restrict flow quite a bit.

In other words, It can be done, but I don't know how well it works long term and It requires a high power pump. If you already have a big (say 1 hp inline) pump running that you can't be turning on/off, then perhaps the solenoid valve branch off to feed the indexing valve might be appropriate, I still haven't talked myself into trying a set up like that myself as it doesn't feel right to me to run that much extra pump power to make the solenoid work and provide a little aeration.