Cistern Valve Flush Control

[Biggles1212]

I use a Cistern Valve for Flush Control. There are many arguments for and against how we control our Flood and Drain, but I saw one on the internet and had to figure out how to make it work. This idea is not my own. The bloke who did it first was also battling with siphons and posted his version. It sounded too simple. I half understood, but had a little faith and went to buy the fittings. Thankfully God was willing to show me how to make it work. My first attempt was Heath Robison to say the least, but the second was finer tuned and allows one to control a lot of the flood and drain cycle.

Looking into your conventional Toilet Cistern you'll have a similar valve. Operating the lever pulls the valve stem up and it starts to flush. Then when all the water is out the system it seals again and fills up. Obviously you can't flush your aquaponic system all day long so we need a mechanism to flush the system. I place my valve in a header tank which is coupled to my grow beds through a balancing pipe. When the valve activates the water drains from the header tank to the fish tank and the water from the grow beds drains into the header tank to the fish tank. To activate the valve I use a pipe extending from the side of the header tank which fills the 2L bottle. The pipe also guides the bottle up and down through the operation. Inside the header tank the pipe can be adjusted to control flood height. The wooden see saw is my linkage from the bottle to the valve.

When the header tank fills up sufficiently it overflows into the pipe feeding the 2L bottle. The bottle has a 3mm hole and starts to drain immediately. However the bottle does fill up faster and so gets heavier. When it is heavy enough it pulls down on the lever and opens the valve. The system then flushes/drains which ever you prefer to use. The bottle will continue to drain through the little hole till the weights above the valve are heavier than the 2L bottle and it will close again. Then the grow beds start to fill up.

By adding weights above the valve you can control the length of the flush/drain. More weights means the 2L bottle fills more and then takes longer to drain out the 3mm hole. So by watching the level you can either ensure a complete drain or choose a minimum level to drain to by adding and removing weights.

Size of pump is no longer such an important factor, as long as you can get water into the grow beds faster than it drains through the hole, then it will eventually flush.

Here's and overall view of the new system.

Just before flushing. The see saw lever is level. Kind of.



During flushing the bottle has filled and flushed the system by pulling down on the lever and opening the flush valve.



A look inside the header tank with the water level high enough to drain out the red elbow to the 2L bottle outside.



A few second later this happens as all the water drains out, more water comes from the balancing pipe into the header tank. The drain is aggressive so I believe it will pull a lot of air into the grow beds.



The water is draining out the 2L bottle through a small 3mm hole. Increasing this hole increases the length of time the water maintains maximum level. Put a small filter in the bottle cap like those green scrubbing pads. Bugs love water and can block those holes. A weekly checkup is to remove the cap and clean anything you don't want in it out.



The old and the new. The old one worked so well, I won't try auto siphons again. I've learned a few tricks to make them work nicely. The linkage to the valve has slack to allow the valve to align on its seat. Very Important. Keep bugs out the 2L bottle. More important.



This system does require maintenance, but my family can't stay away form the aquaponic system so I'm always looking and tinkering. Every afternoon at 16h45 I sit for coffee with the wife and my four boys. We feed fish and talk about the day. It is absolutely peaceful in our garden and everyday, I know I'm blessed.

[Biggles1212]

The main reason for the Cistern Valve Flush Control was because I had difficulty with the sizing of the pump vs auto siphon. As we all know if the flow into the grow bed is too fast, the siphon starts and never stops. If it's too slow, the auto siphon never starts. So as filters clog and time passes, the end result is normally a siphon that won't start. That's to say if all the other plumbing is correct. But who wants to fiddle constantly with valves. I didn't and getting the right plumbing fittings where I live is very difficult.

My aim is to build 24m² of grow beds and 10 000L of fish tank so I bought a suitably sized pump to do all the work. This system allows me to build and add on grow beds and add fish over time and take their growth into account. It also keeps fish densities low. I don't pump any air into my system as the fish density is low enough. Great for a country where electricity is never guaranteed. When I have sufficient solar panels etc I can think about putting more pressure on the system. This valve is controlling the levels whether I use a 50w pump or a 375w pump.

The bigger your pump the faster the grow bed fills. I over sized my pump and allow water to recirculate in the system. This is to encourage matter to settle in the grow bed. The system does have moving parts and that is a weakness. The rubber for the seal will eventually be replaced. So far the only problem was with bugs who find their way into the 2L bottle. I do a daily check on my system and haven't had any major issues with taking off the bottle top, blowing out a bug and putting it back.

All the plumbing is 2" piping so the water really moves fast. So far the system never requires tuning, but only takes second to adjust if you do.

[jackalope]

Quite the system .... I've been brainstorming for something similar (but different!) I love it!
I don't care what country you live in, you're a Redneck! (Rooinek?) I Redneck most of my things as well!
We Rednecks gotta stick together!

[Oldandfound1]

Hi Biggles1212,
Thank you for the photos of the flush system. I have seen other similar valves here at DIY and at YouTube. I can appreciate the aggressiveness of drain in the "water only" operation. Is it your intent for a media grow bed to be used in this system? If so I would for see issues with roots entering the equation, particularly of the upturned red elbow, and possibly of the mechanism of the valve. Any thoughts?
Dennis,
Oldandfound1

[badflash]

This is the barrelponics method. Higher cost than a simple bell siphon, but needs less attention.

Sizing a pump is not difficult, and maintenance of a bell siphon is very simple, as long as your drainage system is designed to be cleaned.

The ones I've built so far trigger at around .5 GPM, so low fill rates are not a problem. They handle over 15 GPM, so the high end is no issue either.

[Biggles1212]

Hi Jackalope, thanks for the comments. It's been quite and education building this system so far.

Oldandfound1, I've been building a system in my mind for a while. Not just the aquaponics, but the whole self sustainability thing. I would love to be able to build a house with everything integrated. So far my gray water recycling system is working well. The aquaponics will also include worms and three different growing systems. The first is the 20mm gravel for filtration, the second a Deep Water Culture and a Raised bed system with lots of worms and vermiculite and also for filtration, but a sump will be included to return water back to the system. The raised bed will only be watered twice a day for growing carrots and potatoes. I plan to container some fruit trees and drip some water to them. It's a big project.

The valve is remote in it's own tub/bucket for now so no issues. I've thought of integrating it into a 2mx1m grow bed, but I've seen how wondering roots attack the shrouds in some bell siphons and the result for this valve would be no different.

Badflash, I would have loved to build a proper bell siphon with all the fittings, but I can't even source a tank adapter locally. Had the parts been available I might not have gone this route. For me it's very important to have my tank sunk in the ground. It gets very hot here.

[Hotrodmike]

Welcome Biggie
I understand burying the tank for heat I did the same here in Texas .
Understand your location and being hard to find parts and I think you did a great job with what you could find
If it works,grow it !
Have A Kind Day
Mike

[badflash]

By "tank adapter" do you mean bulkhead fittings? If so, these can be mail ordered. I was put off by bell siphons until I finally jumped in and built a couple. I made mine from staight PVC tubing and 1/4" aquarium air line. You can make bulkhead fittings from PVC electrical fittings. I'll bet you can get those where you are.

Nice job on your rig, BTW.

Badflash, I would have loved to build a proper bell siphon with all the fittings, but I can't even source a tank adapter locally. Had the parts been available I might not have gone this route. For me it's very important to have my tank sunk in the ground. It gets very hot here.

[Biggles1212]

Hi Hotrod and Badflash,

Unfortunately parts are in limited supply but can be easily ordered from the main centers like Johannesburg and Pretoria. The trade off is the postage which can be quite heavy and unreliable. I've donated enough to our governments postage service so I tend to use couriers only and hence an inflated cost.

I have a town about 4 hours south from here where I buy my fittings when I get a chance to go, but once again, it has to be reckoned into the cost. With the full size greenhouse being built it will make some options more economic.

As for now I'm OK with the system and it keeps working. The nice thing about the see saw lever is that I can see it working. I put a little filter in the bottle cap because it prevents small bugs getting caught in the drain hole, but I still check it every day.

[Biggles1212]

Hi All.

The Cistern Valves have really performed well over the 8 or so months I have used them. I managed to find a suitable fitting to build a bell siphon into but not the right pipe sizes. I made a plan with 6 bar HDPE 1" plastic pipe. By heating the plastic and forcing it onto a swage nipple I manage to form a reducer fitting into it.

This was then fitted onto a 3/4" white pvc pipe which fits snug into the adapter. A 3" pipe was then used to make the bell and voila it works. I'm using a 40cm drop below the grow bed before it drains into the return drain pipe. The new bell siphons have worked flawlessly for the last two months so I'm happy to report that where height permits, I will only use bell siphons.

I've found the cistern valve limits you to a 150L grow bed but definitely avoids the height issue required by bell siphons to work properly.

The cistern valves I found had to be protected from sunlight as they tended to grow huge amounts of Algae in my very first one which then clogged the drain hole in the bottle.