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Fully Automated Water Change System

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#1 asiobob

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Posted 12 August 2012 - 09:13 PM

Before I joined the hobby (with a 6x2x2) one thing I wanted to do was automate the water change process. As you can appreciate, there's lots of different ways to do water changes, however I was after a completely automated solution.
For many the effort of this solution will probably appear as over engineered, however I found the electronic and programming both challenging and interesting (I'm new to electronics, less so to programming).

A micro-controller does the following
* Opens a solenoid valve which causes a treatment barrel to fill up with water. A switch indicates to the controller when the max level is reached
* Treats the water with water conditioner through a Peristaltic dosing pump
* Heats the water (I actually don't have the heaters and may decide not to bother)
* Partial drains the aquarium, a float switch indicates when the drain is complete.
* Fills the aquarium, a float switch indicates when the max level is reached.

This happens every sunday at 9am :-)

Below is a pictorial overview, everything you see here is 12V. This is not a build guide, this post doesn't cover the software aspect (which I made from scratch).
The general process is as follows.

1. Like all good things, water comes from the tap. Of interest would be the black poly pipe which is burried in the garden and is out of side

2. A solenoid box I picked up at Bunnings.

3. Inside the solenoid box: A 12v solenoid that electrically allows water from the tap to be opened and closed.
(the exposed wires you see are a flyback diode and I'll explain this in another post)

4. This is a 210L Rain water tank you can get from Bunnings for a 100 bucks. When the solenoid is opened this container is filled.
Unfortunately I didn't grab pics of the inside, but it's worth knowing there is
1. Float switch to indicate when the tank is full
2. A dosing pump to add conditioner
3. Provision for a barrel heater (probably the only 240 component if implemented)
4. 12v pump to pump out into the aquarium - see image 6, it is the same pump.

4.1 Here's a top view of the barrel (get a decent drill, its a very think plastic lid)

5. Now we move into the house. Perth homes often have double brick making any hole a mission.
I suggest you find a tradesman with a core drill (and about $100 in change). The result will be the cleanest cylindrical hole.
There is a risk the plaster will crack on the drills exit. For this reason it was drilled from the outside in and any lost plaster on the inside can be patched up (or hidden by a flange which I don't yet have)
Make sure you line the inside of the hole, otherwise you'll fail your terminate inspection.

This has two pipes (water in, water out) and some cabling for the solenoid, pumps and float switches

6. This pump (ebay) is a 12V 1amp pump. Right now I just dunk it into the tank. Going forward the pump will be inside the cabinet (below the water line) - less things in the tank, and the pump don't go biological on me.
You don't really need a powerful pump here, there's zero head height as the pipes terminus is below the water line.

7. Now to the automation. I've used custom, open source micro-controller. It looks neater when the cables are tied up and the box is closed. The red circuit board is the real time clock so I can schedule my water change.
The code I wrote from scratch, much to improve but it does the job. Happy to share if anyone wishes to replicate :-)

8, One of problems with pumping out water from the aquarium is that once the pump stops water continues to flow due to the perfect siphon that is created. A micro-solenoid valve wired in parallel to the pump fixes that. When there's no power the valve is closed and no accidents occur,

9. I'll get a full shot of my tank later, till then here's a video of it

#2 garlic shrimp

garlic shrimp
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Posted 12 August 2012 - 09:19 PM

awesome mate ,well done. smile.gif

#3 asiobob

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Posted 12 August 2012 - 09:19 PM

The main challenge is the "general purpose" nature of the micro controller I'm using. It's actually supposed to be controlled by a computer via USB cable. Instead I re-wrote the "firmware" so it automatically did a water change without a computer plugged in. The problem is I have no idea of the status of the water change system when its running unless I have a laptop plugged in. The controller has a limited number of output pins which are being used to switch pumps and solenoids so I may have wire up some LED's in parallel to provide a crude status indicator.

I'm also tempted to design and fabricate my own control board, then I can have an LCD display, buttons and the rest of it for a truly independent solution. I'd do this if others were interested :-)

#4 tusken raider

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Posted 13 August 2012 - 05:30 PM

Wow! Great work.

#5 procull

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Posted 14 August 2012 - 09:06 AM

any idea of costs to set this up for a 5000 ltr system ?

#6 asiobob

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Posted 14 August 2012 - 04:35 PM

For my system: (though I spent more due to lessons learned events)

The micro controller is ~ $180
The float valve switches: ~$10
Power supply: ~$50
Pumps: ~$30 each
Tap Solenoid: ~$30
Anti siphone solenoid: ~$20 each
20M polypipe: $6 bucks!
General hoses: I used 10mm line, but this has to match your pump.
Treatment tank: $100
Misc stuff: $40 (table ties, electrical tape, drill bits etc)
Marine bus bar: $30

For a 5000L system:
you would need a bigger pumps to complete the change in a reasonable time, if you used 240v (rather than 12/24v) then some extra costs for a sparky and other components to eliminate exposure.

#7 lawdog

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Posted 18 October 2012 - 09:32 PM

Well I would be keen on this idea, the extra inputs would be great and how about a basic lighting controller on a secondary timer for led lighting.

#8 ronaldskitz

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Posted 26 October 2012 - 07:30 PM

That is awesome mate sounds like a lot of trial and error but worth it

#9 asiobob

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Posted 28 October 2012 - 08:05 AM

Thanks everyone. The system is working remarkably well. It makes keeping a 6" tank of 35 mbuna much easier.
The plumbed aspect means no mess, and the automated aspect means I can do this whilst I'm away (although I still would like someone to supervise just in case)

One question though...
When you do a water change, do most of you stick a hose straight into the tank allowing tap water in which is then treated with conditioner for the tanks volume? Or do treat the water seperately like I do?
If there's little harm in the first option I would prefer that (it gets rid of the barrel [I don't heat the water anyway], gets rid of a float switch and pump as well)

#10 Juls

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Posted 28 October 2012 - 06:54 PM

Most of us keeping cichlids just put the tap water straight in the tank, Dose the whole tank with dechlorinator before you start, and after you finish.

Of course if your doing a "large" water change, say more than 40% then you should try to equal the temperature and hardness values first.

everyone does things a little different, some won't admit how slack and sloppy they do there water changes, the reality is most (but not all) cichlids are tough and it's not a issue whatever you do.

if you start messing about with very small, rare, difficult fish, then the water has to be perfect match during the change or you lose the lot.

The biggest "BUT" to just tap watering into the tank straight, is that sometimes your local water might change, some places it changes all the time, others it's very stable,

Should you have it setup auto, and one day a main breaks down the road, and they fix it, then your tank gets filled with muddy horrible water that you have no idea whats in it.

The other thing that can happen is they can change there chemical routine if there is a problem, which might cause you problems, There is a risk involved, you need to work out what the risk is with your own experience of your water source.


Edited by Juls, 28 October 2012 - 06:56 PM.

#11 exomoons

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Posted 12 November 2012 - 06:04 PM

First of all, big thumb up for the write up. welldone.gif

I think you could do this with just three 7-days digital timers one or two solenoids and one or two pumps with some tubing.

You would have one timer for the solenoid-rain water tank, just calculate the amount of water flowing per minute and set the ON time so when the water level in the tank is 80~90% full the timer cuts power.

Another timer would be for the pump which drains water out from the main tank. Again set the time for the correct water volume needed to be removed. If you use a pump for this then you will need to make a hold at the drained water level so when the pump stops the flow also stops due to air. If a solenoid is used then it just shut off but the flow still there, the flow should continue for the next water change.

The last one would be used for the pump pumping water from the rain water tank to the main tank..and once again set everything to the correct L/min and it should be fine.

If I were to do this then I would sync three timers and set the rain-tank's on a Monday, leave it for 7 days to age the water. The next two timers will be set on a Sunday consecutively.

Just a thought.

#12 asiobob

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Posted 17 November 2012 - 08:36 PM

yup that would work (and work reasonably well). my micro controller is effectively a super-duper timer - I have timeouts set so that if something happened to the float valve the (water) damage to the house would be limited/avoided biggrin.gif
I like my system because
* I made it biggrin.gif
* I can remotely trigger a water changed (tested already works well when I'm away on work)
* I can do adhoc water changes at the touch of a button
* I can move the float valves around to change volume
* If one step fails, the entire program stops and alarms (so for example, an already filled aquarium that failed to drain won't get topped up with fresh water...)

Regardless of autoamation method, it's helped keep my tank healthy and fish keeping more enjoyable

Edited by asiobob, 17 November 2012 - 08:37 PM.

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