Backyard Aquaponics
A place to discuss aquaponics

you don't need flouts or autosiphons on the fish tanks,
only a siphon drain on the top tank (what is commonly but wrongly called a venturi drain)
and overflow siphon drains (same as on the top tank, but limited to a certain level)
(unless you want fish in the top tank too in which case that must be an overflow siphon drain too)

autosiphons and flouts are for the growbeds

frank

electric and hydraulic diagram
feel free to ask questions

greetings

frank

I'm confused about the whole siphon drain thing. I thought the whole purpose of a "venturi drain" was that it does not siphon. It sucks stuff from the bottom of the tank but does not siphon at all.

sucking things off the bottom is exactly what a siphon does
http://en.wikipedia.org/wiki/Siphon

frank

Really neat idea! Thanks.

Yes. I will have a "T-type venturi drain" on the regular Fish ponds. It is how I know to call it. Am I wrong? Would it not only be a siphon if the top vent was capped to induce siphoning? Would that not then empty the Fish Pond? I want to lift solids from the lowest base of the slope of the Fish Pond and liked the ease of installation and maintenance of this T-type model. I was thinking of putting in 4 of these along the edge.... one into each long GB. I'll put a pic. Would the extra not effectively act as an overflow? I suspect the overflow is needed in case something got blocked.



Yes. A new idea from OBO. Really neat use of all that water. Might just use it for some speciality-use like fingerlings..... very little solids added to this return water.... but have to find a way that they do not get sucked out into the Fish Pond....



Yes. Rapid exit of water draws in oxygen. Good for plants and good for fish. I suspect the flout would be the fastest and most efficient. What do you think?

Does it not do it while emptying the whole tank Frank? I also thought that was what made it different to a drain.

Ahhh! The perfect time to call on those dumb questions I have lined up.... This is extremely new to me.

I see the 2 circuits in parallel. A slow and a faster exit of water from the Fish pond. The slow flow is always open. The faster flow is open when there is power...... power fails..... NC (normally closed) valve closes......

OK....

Question 1...... if an NC valve is normally closed and closes when the power fails.... .... yip I am drowning. Is it that an NC valve is actually an NO valve? (normally open).

Power failure trips a switch which shuts the valve. Water travels on via slow piping network.

Question 2......Bipolar fuse to stop overload damaging hardware? Or is it a special thing for this design?

Question 3.......Header tank level switch? Why is this needed? Does it ensure the fast network kicks in only at really elevated levels? Higher than the drain level?

Question 4..... Those 2 power outlets.... Just 2 circuits from one power source?

I would like to avoid timers if possible. I understand that they can make life easier in certain situations... but I am hoping to train staff to maintain my system when commercial and prefer to avoid unnecessary technology. I might change my mind about this later... of course... a well-used woman's perogative

I think i want to understand these questions first before I get even more confused...

I definitely need that Bike right NOW!

Thank you for your trouble Frank. Really appreciate it.

Frank,
Here are what we are calling ventri drains


I don't think either type could be called a siphon but they will work just fine for bringing solids off the bottom of a tank without risking siphoning or draining the the fish tank down below the intended water level. They are pretty simple but do require a hole plumbed through the tank to be this simple. No worries of an air bubble forming and stopping it. No worries about loosing the siphon.

Yes Cyara, having the 4 venturi drains will give you in effect an overflow from each fish tank so if some blockage happens you won't have too worry too much.

I still don't think you will want to have a flout in the top tank. Just put some grow beds between it and the top fish tank so the fish tank will get the aeration. If you put a flout in, you will loose much of the water from that tank in one flush leaving you with little left for loss of pumping reserves. Then again, I spose a flout could be mounted high up on the side of the tank with a ledge under it to stop it flopping down too far. So it might only flush or drain the top say 8-12 inches of the top tank.

Yes. This is what OBO meant I think. Raise the flout. Plenty of water storage up top but only need to flush out enough into the Fish pond for the first unit of GBs. The extra water can then be used in a secondary way.... fingerling initial grow-out or something. Am just concerned about not flushing the babies through the flout though.

Should the stored water be needed in an emergency.... simple pipe feed - at a lower level - into the normal network with a ball valve or something to plug it until needed.... or a series in ever lower levels ......until a plug/valve at the bottom too ...for complete drainage.

I am thinking about this and how it could best work for me.

To keep babies from being sucked out, you would need intake grills around any outlets. They would need to be fine enough that the small fish wouldn't even try to swim through. This would make maintinance more of an issue since screens, grills, etc all get clogged easier.

For the flout, I would build a screen or fine net box to install all around it since you not only don't want the fish to be able to swim into the flout and get sucked down, you also don't want them to get smooshed by it when it sinks to the bottom of it's shelf.

So what happens if you have fish in that header tank and you don't have any pumping going on for a while?

I figure for speciality use it should be OK. Few solids produced and tilapia accept such unprocessed water from me now. The fingerlings grow quickly and then will probably have a better chance in the main ponds. I think they are getting eaten at the moment.

Is just thoughts at this stage.....

Cages for the fish are my answer to controlling breeding in the tilapia tank. I have one big cage with most of the fish in it. Another smaller cage I can place in that same tank if I had a smaller batch of fish I wanted to keep separate. and a really little cage to put any of the fry that have gotten big enough not to swim through the netting. Only problem with separate cages, you then need to feed them separately and lots of the food can tend to float through the cage where the tilapia can't get to it. So I have some catfish living outside the cage to clean up the loose food.

I have found that if you put hides into the bottom of the cage, the tilapia can manage to breed. so if you want to avoid uncontrolled breeding, no hides.

As to the babies getting eaten, I suspect the other babies are more likely to eat the smaller babies than the larger adults are.

That is interesting.



By "hides" you mean animal skins?



I thought babies only ate algae? Could explain why only ever got one set of babies!

first let me explain in simple terms how a NC electrovalve (solenoid) valve works: a spring loaded cylindrical piston (sometimes attached to a membrane) closes the water passage. A coil (solenoid) is located just above this piston. When current passes through the coil a magnetic field is created that lifts the piston (compresses the spring) and frees the passage, the water flows through as long as the current keeps the magnetic field active. Cut the current and the magnetic field is no more and the piston is forced back in place by the spring (these springs are very light, the water pressure helps to close the valve).
So the "action" is not the closing of the valve but the opening of the valve. Hence this kind of valve is called NC (normally closed, since in rest position, without current, it is closed. Cut the power and the valve will return to it's rest position, closed. NC.

No, power failure interrupts the magnetic field and the spring drops back the piston to where it closes the valve.
So there is already one major condition for the valve to open: there must be current.
The level switch I have drawn is there to create a second condition: there must be enough water in the tank to open the fast lane.
This switch is activated by the level of the water in the tank.
I have drawn the switch as an exchange contact as this is the most frequent (some have a single contact)
The exchange contact has one entry (called the common, and indicated with the letter C) and two exits: a NC exit and a NO exit.
Knowing what NC and NO means, it will now be clear to you that in the "rest" position (no water in the tank), the current is bridged to the NC exit and cut to the NO exit. This is the normal position. If there is current, it will flow from C to NC and not to NO (to which the solenoid must be connected).
When the water rises over switching point, the switch is forced to the other side (the "not normal" position) and the current will flow no more from C to NC but from C to NO and to the solenoid valve. A magnetic field is formed and the valve opens.

A fuse is there to cut off the current in case of overload, i.e. a short circuit or a stalled pump.
Bipolar fuses are mandatory in Europe for all "wet" rooms (kitchens, bathrooms): in case of a short circuit BOTH conductors must be cut off.
Another thing that is mandatory for all "wet" rooms in Europe is what we call a "leak current" switch.
The fuse protects against overload, the "leak current" switch protects you against electrocution in case of a small or bigger current flowing to earth.
As you are constantly working with water this is strongly advised.

is already partially answered: it ensures the valve stays closed as long as a certain level is not reached, so only slow flow is coming through and at the moment you consider that there is enough water stocked to help you through the next period, it lets the current pass to the solenoid which switches the valve to it's open position.
(by the way, I forgot to draw a manual valve above the solenoid valve which you will need to regulate the flow through the fast lane)

They are not power outlets but power inlets.
Power source can be either alternating current (AC) or direct current (DC)
In a DC system (mostly 12 or 24 Volt) you have a positive (+) (red) and a negative pole (-) (blue).
In an AC system, the poles are inverted at a certain frequency (50 or 60 Hz) so each pole turns from + to - and vice versa at a speed of 50 or 60 Hz.
A (day) timer is optional and will allow you to have different regimes at different times i.e. day/night should you wish that, still under the above described two conditions: there must be current (main condition) and there must be enough water in the tank (secondary condition).
A timer is a very simple thing, and is reliable and cheap.
I would not install one if you are on wind pumping (or switch it off if there is enough wind - this can be automatic with a simple wind detection switch in series with the tank level switch and would ensure maximum possible water sparsely used when the wind drops), I probably would as long as you are not wind pumping.


You don't need flouts or autosiphons on any of the tanks, only overflow siphon drains
You need constant feeding of the growbeds
all autosiphons or flouts must be on the growbeds to ensure fast draining.
(as soon as my sketchup drawing of different drain systems and the names I think should be used is finished I will post it in the sketchup thread)

Hope this further increases your confidence.
You will have a very nice system.

Frank