# My automatic water changer system concept



## PDX-PLT (Feb 14, 2007)

Hi,

Reading many of the posts on this site (especially Scolley's) has inspired me to plan an auto WC system for my planned living room tank. This is a description of what I'm thinking of doing. Comments are welcome.

Some initial criteria:

-- I'm on well water; no need to worry about dechlor.

-- I'd like to minimize pipes going into the tank, but I not going the drilled tank route. But I'd like to use the filter intake and outflow pipes.

-- At the same time, I didn't want to put anything restrictive in the path normally used by the filtering system; that rules out most reasonably-priced solenoid valves.

-- I was first planning on running two pipes down to the laundry room, one for drain and one for fill. Then I realized they're never used simultanously, so I could run one fairly large diameter pipe (maybe even 1/2") and use it alternately for draining and filling.

-- I'll have a glass top, so I can hang level switches from it.

OK so here is the concept:










At the top are two liquid level switches used to determine the "Full" water level, with output signals Full-1 and Full-2. I use two for redundancy, since this is a very important function to prevent flooded floors.

Water can be drained from the tank by turning on the drain pump, Valve-1, and Valve-3. Water can be put into the tank by turning on Valve-2 and Valve-4. These four valves can be relatively inexpensive diaphram valves, as the drain pump and fresh water supply provide substantial pressure.

The check valve prevents any chance of the drain pump draining the canister filter and causing it to lose prime. This is a big check valve with 1.25" inputs, and a CV factor of 190(!). At 5 GPM flow, the pressure drop through it is 0.03 PSI. The valve also means there's no concern that the fresh water supply, when in Fill Mode, will flush crud out of the filter and back into the tank. This is a picture of the check valve and one of the subminiature level switches, with the Coke can for scale:










The adjusting valve can be used to reduce the flow from the fresh water supply in Fill Mode. I may also need an auxiliary heater to warm up the incoming fresh water: "back of the envelope" calculations show that with the one 300W Hydor inline heater in the system, I can only put in 1 gallon every 4-5 minutes. To up that, and be able to keep the water warm, I may need to turn on an auxiliary heater.

All of this is going to need some type of controller. The plan is that when the WC controller receives a trigger signal, from a timer or perhaps a PC application, it will start a drain/fill cycle. The following would then occur:

-- The tank is normally in an "overfill" condition; i.e., filled to a level a little above that needed to turn on the level switches.

-- When the Trigger signal is received, the WCcontroller first checks that both Full-1 and Full-2 signals are True. If either one is False, the controller turns on an alarm (now just a buzzer, but eventually could send and SMS message to my cellphone), and stops.

-- If Full-1 = Full-2 = True, then the controller drains out some water for a short time T1. T1 is long enough to guarantee that both level switches go to False if they are operating properly.

-- At the end of T1, if either Full-1 or Full-2 are still True, the alarm is turned on, and draining is turned off.

-- Otherwise, we know at this point that, fairly recently, both level switches read True when they were supposed to, and they both later read False when they were supposed to. So we can have confidence in them to proceed further. Draining continues for a period T2, which is chosen to be long enough to drain the desired amount.

-- At the end of T2, the controller stops draining and, after a brief pause, begins filling. It also starts timing a period T3. T3 is timed to be long enough to guarantee that the level switches will go True: in other words, if they don't both go true by the end of T3, something is wrong.

-- When either Full-1 or Full-2 go True before the end of the T3 period, the T3 timer is stopped, the controller continues filling, and starts a brief timer T4. If T3 expires before either Full-1 or Full-2 going true, then filling stops and the alarm is set. This prevents flooding the floor if both switches malfunction.

-- At the end of T4, filling stops, The tank should be in the proper "overfill" state now. If either Full-2 or Full-2 are still False, the alarm is set.

So I still have a bit of work to do. A design for the controller based on an Atmel AT89S51 microcontroller is here:










I included relays to turn the canister filter and the inline heater on and off as well, in case I need to. I also added switches to manually put it in either Drain or Fill mode. A 24 VAC power supply is included that can be used to operate the 4 valves. I got the PCB board design pretty much done. Now if I can just find the code to the last 8051 microcontroller project I did about 12 years ago, I'll have a jumpstart on doing the code.


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## mistergreen (Dec 9, 2006)

cool.
I was thinking of doing the same but I have to dechlor my water supply and I have no Idea how that can be done accurately.

Maybe you can save $$$ on not buying a drain pump and do like this?


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## Gatekeeper (Feb 20, 2007)

can you get away with using the filter as your pump for the drain line?? In other words, move the drain to the outfow of the filter and just have a by-pass switch that turns either the return line to the tank and drain line on/off? Or if you can get away with just the head pressure from the siphon of the tank, you could just drain it without a pump. Be sure to have the filter turn off though!!!!

with all those controllers, what happens if you have apower outage during the drain process? Are they powered switches that will turn off or close when there is no juice?? Same with the floats i guess too.

Here is a link to another water changer system using X10 controllers instead of a processor.

http://www.plantedtank.net/forums/equipment/34969-my-automatic-water-changer-setup.html


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## bpimm (Aug 2, 2007)

You can also use an overflow box, like the ones they use for a sump system, then you drill that and set the water level in it with an overflow drain. then regulate your incoming pressure and use a needle valve to control the fresh water. always topped off, no electronics. can still add the float switch to a valve on the incoming water in case the overflow plugs or looses the siphon. 

But then if you want the electronics that's a cool project by it's self, I've always been a fan of simplicity. and I know my experience with commercial electronics leads me to not want them involved in keeping the water in my tank. 

The reliability of your own design may be better tho.

I know that gravity hasn't had any downtime so far, at least to my knowledge.


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## PDX-PLT (Feb 14, 2007)

mistergreen said:


> Maybe you can save $$$ on not buying a drain pump and do like this?





gmccreedy said:


> can you get away with using the filter as your pump for the drain line?? In other words, move the drain to the outfow of the filter and just have a by-pass switch that turns either the return line to the tank and drain line on/off? Or if you can get away with just the head pressure from the siphon of the tank, you could just drain it without a pump. Be sure to have the filter turn off though!!!!


I thought of doing that, but I think in order to get good flow on the drain line that's predictable, and doesn't require a pump anyway as you did, it requires putting a valve in the return path from the filter (it's a long way to the laundry room). Solenoid valves with high CV factors that won't unduly restrict normal filter operation are very expensive; more expensive than a utility pump.



> With all those controllers, what happens if you have a power outage during the drain process?


 It's just one common controller. If it loses power, the relays will get to a state where the valves are closed, the drain pump is off, and the filter and heater get power (assuming there's still power in the house).



> Here is a link to another water changer system using X10 controllers instead of a processor.


Yes I saw that; it was one of the inspirations for this work.



bpimm said:


> But then if you want the electronics that's a cool project by it's self, ...


Yep, I'm a natural tinkerer (alot of folks here seem to be), and didn't want to go the drilled tank route this time.

Looking it over, I think I'll need to make a slight modification: When closed, Valves 1, 2, and 4 experience reverse pressure. This will pop open cheap diaphram valves, so I'll just need to add some cheap check valves on each of their outputs.


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## scolley (Apr 4, 2004)

Very nice setup PDX-PLT! I hope you build this, as I'd love to see the results.

A couple of comments:

1) The use of a single PEX line for drain and fill is ingenious. But the problem I see with it is that your 4 valves are all going to have to be controlled by the same controller. So one way our another, you are going to be running not only the PEX, but also the power/control wires for the valves. If you just simplify this and run two PEX lines (one drain, one fill), it will be less clever, but you can reduce this down to 2 valves, and not have to run electrical wires along with your PEX.

2) I initially used a pump as you are. But I'm not using PEX tubing, I'm just using 1/4" tubing. The pump was nice, because it gave a nice predictable flow rate. Problem was, I found, was that the flow was no faster with the pump than without. The friction of a very long run of 1/4" tubing was so significant that both using no pump - just the head pressure of the water - and using the pump peaked out at just the same rate. So the pump did little good. But in your case, that PEX is larger diameter (I assume) so you may find the pump brings value. I look forward to finding out.

Good luck! Go for it!


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## PDX-PLT (Feb 14, 2007)

scolley said:


> Very nice setup PDX-PLT! I hope you build this, as I'd love to see the results.


Steve -

Thanks for the kind words. Some vacation time has allowed me to make some progress on the controller. 

I found a great system for making homebrew PC boards. It uses laser printer toner printed on a special paper with a water-soluble coating to make etch resist patterns. The little company that sells the paper is www.pulsarprofx.com (I have no affiliation with them). Some thumbnail pics:

   

In the first, the backside trace pattern is printed out on my ancient HP Laserjet 4P. In the second, the toner's been heat-transferred to the PCB by running the board and the paper through a laminator, and then placed in a water bath to release the paper. In the third, a green sealing layer that heat-fuses to the toner has been attached by running the board through the laminator again with the green film, and in the fourth the uncovered copper has been etched away by putting the board in a nasty chemical.

More pics:

   

The fifth pic shows the copper traces left after the green film and the toner's been removed. The next pic shows the top side, which is mostly ground plane. In the seventh pic I've used the toner transfer again to label the top of the board as to which components go where, and label the connectors. The last pic shows the components all installed.

Now I have to write a little bit of 8052 assembly language; it's been about 15 years since I've done any of _that_. 




> A couple of comments:
> 
> 1) The use of a single PEX line for drain and fill is ingenious. But the problem I see with it is that your 4 valves are all going to have to be controlled by the same controller. So one way our another, you are going to be running not only the PEX, but also the power/control wires for the valves. If you just simplify this and run two PEX lines (one drain, one fill), it will be less clever, but you can reduce this down to 2 valves, and not have to run electrical wires along with your PEX.


I'm not at all concerned about running some low-voltage wiring in parallel with the tube (I'm using 24V valves). It's small, flexible cable that's easy to run. Worst case, I could always use something like Insteon or Z-wave or Zigbee to control them remotely. Either way, it's easy to me than running water lines.



> 2) I initially used a pump as you are. But I'm not using PEX tubing, I'm just using 1/4" tubing. The pump was nice, because it gave a nice predictable flow rate. Problem was, I found, was that the flow was no faster with the pump than without. The friction of a very long run of 1/4" tubing was so significant that both using no pump - just the head pressure of the water - and using the pump peaked out at just the same rate. So the pump did little good. But in your case, that PEX is larger diameter (I assume) so you may find the pump brings value. I look forward to finding out.


I'll just need to experiment with/without the pump once I get it set up. The water drains down to a room one floor downstairs, so I could very well end up being in the same situation as you and not needing the pump; if I need it I've made provisions for controlling it.

I'm planning on running 1/2" pipe, same as most plumbing pipe, which has 4x the cross-section of 1/4" tubing. I could just use black polyethylene, but I'm going with the cross-linked polyethylene (PEX) that plumbers use since it's alot tougher, it's going to be buried in a wall, and it's still pretty cheap.



> Good luck! Go for it!


Thanks for the encouragement and the input.

--Barry


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## Gatekeeper (Feb 20, 2007)

thats not just tinkering bro...thats just insane cool. way to go....I am so psyched to see this thing in its final setup.

I got my fingers crossed that it works out for you.

Is there a way that you can run testing or diagnosing on the board you made to make sure it works before going all the distance to completion?


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## tazcrash69 (Sep 27, 2005)

Barry, OK, I am seriously in awe, and subscribing to this one. 
I can't wait to see how this turns out.


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## mistergreen (Dec 9, 2006)

how to make your own pcb
http://www.youtube.com/watch?v=urv6jArKp6M

you can use regular photo gloss laser paper.


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## PDX-PLT (Feb 14, 2007)

The video sums up the process. Conventional wisdom is that the particular Staples brand glossy paper works much better than others. Even so, the glossy paper is _much_ more difficult to use than the Pulsar paper. The Pulsar paper is about $1.40 a sheet, though.



gmccreedy said:


> Is there a way that you can run testing or diagnosing on the board you made to make sure it works before going all the distance to completion?


Yep. I downloaded a little program to the board; it simply turns on the buzzer when any of the inputs are closed (this actually tests most of the board's circuitry). It worked just fine!

Further updates won't happen for awhile; not until I get the tank set up. This means I need to finish the stand (back to woodworking). It's taking a while.


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## Cactus Bastard (Jun 5, 2007)

That pulsarprofx is cool!!
Oh, and your project is really awesome too!


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## vidiots (Jun 17, 2006)

Seems excessively complicated to me, ok I'm hooked, can never get enough of the extremely overengineered..


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## PDX-PLT (Feb 14, 2007)

Update: I got the Controller Hardware all finished.

Here is a clickable thumbnail of the interior: 

Here is the front panel: 

Here is the back panel: 

I put two AC inlets in the back since some of the things I may potentially want to control, like the filter, I may want to put on a UPS. But other things like heaters would drain a UPS quickly.

My LFS had a sale on big (>=75 gallon) tanks, so I picked up a 90 gallon. It's sitting out in the workshop and serves as motivation to keep going on this project. Unfortunately I was gone half of last month on business, and I'm gone next week as well.  But I'll keep plugging away at it.


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## scolley (Apr 4, 2004)

Holey Moley! I am humbled by this! That is particularly true because I don't even know what I'm looking at!

You've clearly done a great job at constructing something tightly configured to your needs. Job well done Barry!

But please, do explain what we are looking at, in particular with reference to your 1st post on in this thread. I'm trying to relate all the connections in the back of your box, and relating them to what you were originally trying to do, but I'm not comprehending all the connections. Can you please explain?


PS - I don't want to hijack the subject of your thread... but I do want to mention that I am thrilled that you are trying to take a practical and affordable approach to auto-water changing without unusual tank modifications. While I may have executed a proof-of-concept, but you are executing a far more valuable real world "you can build this yourself" alternative. Most people are NOT going to drill their tanks, and you a blazing making significant contributions to making auto water changing accessible a larger audience. Thank you.


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## PDX-PLT (Feb 14, 2007)

scolley said:


> But please, do explain what we are looking at, in particular with reference to your 1st post on in this thread. I'm trying to relate all the connections in the back of your box, and relating them to what you were originally trying to do, but I'm not comprehending all the connections. Can you please explain?


Uh, you're right, I now realize i need to put the latest pics in context.

They're pictures of the completed controller whose schematic is in a prvious post. 

The front panel is mostly for looks. I used the same laser-printer-toner transfer process that I used to make the PC board in order to put the graphics and labelling on the panels. The green pilot light just lets me know the box is plugged in and getting power. The left switch is not really needed, but I figured if I'm going to all this trouble, why not add a switch so that I can do manual filling and emptying as well? To drain the tank, just put the switch in the down postion. To add water to it, just put it in the up position. In either position, the controller will put the valves, etc., in the correct state to perform the requested operation. In normal use, you'd never use this switch.

The right switch is used to reset the alarm condition and turn off the buzzer. As I described previosuly, if something wrong is detected during an empty/fill cycle, everything is returned to the idle state and the alarm buzzer is turned on. Hopefully, I won't use this switch much, either. 

The back panel is where all the connections are made. The serial port is currently unused - the microcontroller chip is equipped with one, so I thought I might as well hook it up. In the future I might hook the box up to my PC or something. Below that is an input jack for the two redundant float sensors that detect a Full level.

To the right of that are bannana jack plugs for powering the 4 valves in the system (see the diagram on the first post). Next, to the right of those are 120V AC jacks for powering four devices controlled by the system - the cannister filter, the heater, the drain pump, and a possible auxiliary heater (although I'm working on something else that may obviate the need for that).

Finally, the AC power inputs are on the right side. The UPS input powers the filter. The non-UPS input powers everything else, including the controller box itself. The Trigger input is used to initiate an Emtpy/Fill cycle - just breifly apply 120V to it to start the cycle (I did that so I could set the time of day to do the cycle with a simple appliance timer, or an Aquacontroller, etc., without having to mess with the software in the box itself every time I wanted to change it).

Hope that helps. My brother-in-law, who happens to be a mechanical engineer, has two CNC machines in his garage "for fun" (?), so it was a simple matter for him to do all the cutouts for the switches and connectors in the panels.



> PS - I don't want to hijack the subject of your thread... but I do want to mention that I am thrilled that you are trying to take a practical and affordable approach to auto-water changing without unusual tank modifications. While I may have executed a proof-of-concept, but you are executing a far more valuable real world "you can build this yourself" alternative. Most people are NOT going to drill their tanks, and you a blazing making significant contributions to making auto water changing accessible a larger audience. Thank you.


Thanks. At this stage, it's still only "build this yourself" for electronics hobbyists, of which there seem unfortunately to be fewer these days. But if I can contribute to a gradual progression in the development of auto WC systems that are more mainstream, that would be great. You might have kicked off a genuine 'movement'. 

In alot of ways, the aquarium hobby has progressed alot since when I was a kid. Back then, no one at the hobbyist level knew anything about the nitrogen cycle. But even today, most of us either do a clumsy job with keeping our livestock in what is essentially a miniscule quantity of water compared to their natural environment, or we do a tremendous amount of manual labor. This is in stark contrast to the big exhibition aquariums. I visited two this summer (the Montery Bay and the Oregon Coast), and the stocking rates they can maintain in their tanks is impressive; of course, the reason they can is that they're adjacent to the ocean, and can do massive, continuous water changes. Maybe someday in the future, you'll be able to order plumbing set up for an aquarium as commonly as you can for a bar sink, and there'll be commercial hoobyist aquarium equipment that'll hook right up, that implements a "turnkey" auto WC system.


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## Gatekeeper (Feb 20, 2007)

Man.... I feel very small after reading this thread... very inspiring I must say.


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## Gatekeeper (Feb 20, 2007)

out of curiosity, the cabinet box you have there...what is it and where did you get it? You seem to have perfectly sized this little box perfectly for all the components you have. Was this just luck?? lol.


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## PDX-PLT (Feb 14, 2007)

www.digikey.com 

You can choose from lots of different sizes.


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## PDX-PLT (Feb 14, 2007)

I got a PM with some questions, and I thought I'd share the answers with the whole group:

_I'm confused about your 2 sensors. Why one jack? Why not 2?_

I ran out of room on the panel. Actually, I goofed a bit - I sent the blank panel to my brother-in-law to cut out on his CNC machine, and then realized I had forgot to specifiy any holes for the sensors jacks! So I picked a jack that fit in a round hole that I could drill myself. There was only room for one. No biggie, since the two sensors will be mounted close to each other, and will use a single cable.

_And do they operate so that if one switch closes, it throws the switch? Seems like a good way to deal with redundent sensors._

The sensors don't directly control anything. They just each provide a logic-level input to the controller software when the water level in the tank is above a certain level - 1 when the water level is above that level, and 0 when the water level is below it. I could have used just one, but I figured they're the least reliable part in the system, and if one failed stuck in a "0" state, some water would end up on the hardwood floor (until the failsafe timer stopped it). 'wouldn't make me me nor the aquarium very popular.

_And what is that "trigger"? Maybe I'm missing something, but a bit more description of what this is, and how it works would help me. Maybe other people too._

Yea I guess that's confusing. Here's the explanation: at this point, I don't know how frequently I want to do water changes. 'probably once a day, but maybe twice. Who knows, maybe every other day. So I'm not keen in hard-coding the frequency of the changes into the controller code. Nor did I want to go to the trouble of coding a time-of-day clock into the controller code.

The most straightforward way to schedule this, it seemed to me, was to use an off-the-shelf appliance/light timer (same as what you would use to turn the lights off and on). These are cheap, readily available, and easy to program. That's what the "Trigger" input does. You plug it into one of those timers. When the controller sees 120VAC applied to the Trigger input, it initiates a water change cycle. When this cycle takes place, and how often, it controlled by the timer.


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## Gatekeeper (Feb 20, 2007)

So how is this baby working out for you?


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## PDX-PLT (Feb 14, 2007)

Sorry, not much to report yet. Work, travel for work, building Xmas presents, the holidays, etc., have gotten in the way.  Finishing up the stand is the next task.

I do have one thing to report, though. As I mentioned, I'm planning on mixing both the cold and hot water supplies for the fill water. A tricky aspect of this is keeping a stable temperature. I thought of using one of those pressure-balancing or (even better) thermostatic mixing valves, like the type used for shower valves now. But not only are shower valves expensive, the lowest temperature setting is still way too hot for aquarium use.

Then I found these mixing valves:









They are intended for use with hydronic radiant-floor heating systems. Their lower range is 85 degrees F, perfect for a discus tank. I picked one up on E-Bay for about $40, much cheaper than the thermostatic shower valves.


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## xGROMx (Sep 2, 2008)

I just finished somthing simillar, it's only an auto filler though. I have a 24v transformer controlling an irigation valve through a float switch. The valve worked out great, you can find them at home depo from 1/2 inch to 1 inch is size. as for the water source, i have well water and i have the inlet hose tired into ta garden hose outlet right outside from the aquarium.

My only problem I was when it gets colder i'm not going to be able to fill the tank with the cold water. My solution is i am going to run a new line to the water heater room and tie into the cold an hot with valves to ajust the temp. I was going to post a thread when i fixed it.

PDX-
An easier way than shower valves to ajust the water temp is to use two diffrent valves. One on the hot and cold lines and then T the pipes together. Leave these valves alone once set and use a diffrent valves to use and shut offs.


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## PDX-PLT (Feb 14, 2007)

OK, time for a (long overdue) update: it's all set up!

Now that the tank stand is complete and in the living room, it's time to move the autoWC system in there, too. It's been running in the shop for several weeks, hooked up to garden hoses for supply/drain.

First off, the design has been modified a bit:










With this modification, all the autoWC plumbing at the tank is done on the outlet side of the filter. This makes things a bit simpler, as the inlet side is unchanged. In addition, with this change, all the solenoid valves have filtered water running through them. This reduces the chance that one of them will get clogged, or stuck open from a dirt particle. Also, I added check valves at some of the solenoid outputs. Diaphragm solenoid valves will open with any reverse pressure. Valves 1 and 2 are such valves, so the check valves prevent this. Valve 4 is a direct-acting valve, but it has a check valve on it to help ensure that drain water doesn’t feed back into the fresh water supply.

Here’s what the plumbing looks like under the tank:










With the filter removed to make things easier to see: 










Valves 1,2,3 are from the “valves4projects” Ebay site. They’re unusual for diaphragm valves in that they’ll work at low pressure, down to 0 psi. The inexpensive lawn sprinkler valves need house water pressure (~40-60 psi) in order to function, so they’re not suitable for most aquarium applications. The “valve4projects” valves are great for the price, with high Cv values (i.e., low flow-restrictions).

Valve 4 is a bit more expensive direct-acting valve. This valve needs to withstand house water pressure long-term and is important to the reliability of the system, so I felt it was worth it to spend a little more. As a direct-acting valve, it has a lower Cv value, but it has the benefit of house water pressure to push water through it.

Valve 4 operates off of 24VAC and the oher three use 12VDC; the power center I put together supplies these voltages as well as supplying 120VAC outlets for other equipment:



















Here’s the AutoWC Controller box on the left side of the stand; I still need to clean up the cabling a bit:










I ended up using ¾” tubing in the run from the living room to the laundry room for maximum flow. I used CPVC tubing for long straight runs, and PEX tubing where more flexibility was needed.

For the hole in the living room wall I needed a large hole so I’d have clearance to drill through the bottom plate of the wall, but I wanted it to look neat for maximum spousal approval. I ended up installing an access panel (I later drilled a hole in the cover for the hose that connected to the tank stand):










This gave plenty of clearance for the drill:



















Here’s a shot from inside the wall, showing the hole in the bottom plate and access to the joist space below:










The PEX tubing from upstairs transitions to CPVC with a Sharkbite connector, which is a great system. The Sharkbites are approved for house plumbing and in-wall use (as are PEX and CPVC), and they hook up to any potable water tubing using the CTS size system (copper, PEX, CPVC). Note they don’t work with Schedule 40/80 PVC pipes, which aren’t rated for potable house plumbing.

After this connection was made, I put the square of drywall back into place; a little spackle, some spray-on texture, and touch-up paint made it disappear.










The long run of ¾” CPVC through a utility room, which will be covered with some molding:










Making it to the laundry room, a cabinet was temporarily removed in order to make an access hole to continue running the tubing:



















Here’s the plumbing at the laundry room end. Note the strainer, which guards against a dirt particle getting to Valve 4 and clogging it.










The connections to the cold and hot water supply lines are full-flow ½” lines, in order to allow a fast refill rate. Sharkbite connectors make it easy to connect the pre-assembled module to the plumbing:










Here’s the mixing valve, which does a good job of keeping the temperature at 84-85 degrees. At the beginning of a fill cycle, valves 3 & 4 are turned on for 30 seconds with valves 1 & 2 off, in order to warm up the water before sending it into the tank. Check valves on the hot and cold lines ensure that the cold supply won’t empty the water heater of hot water, or allow hot water to flow into the cold supply:










The connection to the ¾” line from the tank is also done with a Sharkbite.










Some pics of the level sensor switches. The first shows one when the tank is not full:










The next shows it when the tank is filled up:










This shows the mounting of the switch from the top. I have Aqueon Versatop covers on the tank. I didn’t like the hokey plastic strip in the back, though, so I replaced the rear piece of glass on each one with a wider glass piece that eliminated the need for the plastic strip; I drilled and notched a hole in the glass in each for the filter pipes, and drilled a hole for mounting the level switch. Old 35 mm film canisters cover the electrical connections:










This is the initial setup of the tank, to check everything out. I probably won’t put any plants in until the Discus I’m getting grow out a bit. The big take-away from this pic, though, is the complete absence of additional pipes and most contraptions in the tank for the autoWC. The small, tan-colored level sensors in the rear corners are the only extra things.










Here it is with ~40% of the water drained:










Here’s the fill cycle in progress:










With the ¾” line to the laundry room and the full-flow connections, this system is _fast_. It only takes ~13 minutes to drain 40% of the water from the 90 gallon tank, and only ~11¼ minutes to refill it.

After all the years of dragging buckets and dealing with siphons on smaller tanks, there’s no way I wanted to do it with a tank this size. Especially with wanting to try Discus, and the high water cleanliness standards they demand. It’s a great feeling to park your butt in a comfy chair in from of the tank with a cold one, and watch the tank do the water changing chore *all by itself*, as if by magic. It’s a satisfying feeling.


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## yikesjason (Jul 2, 2008)

Amazing system. 
Where are you going to get your discus? 
Do you plan on using a gravel vacuum at all?


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## PDX-PLT (Feb 14, 2007)

Thanks.

I prefer the European Stendker lines over the Asian imports, so I'll probably go with those. The Wet Spot is a Stendker dealer and has had some decent looking stock in the past, but the last time I went in there I was, quite frankly, appalled at their condition. Maybe the economic downturn means they can't afford enough people to keep up with maintenance? I dunno. Since Hans (the USA Stendker importer) now takes orders direct, I'll probably get them right from him.

I have a very thin (<1/4") layer of sand on the bottom right now. I got an Eheim Sludge Extractor, which seems to do a decent job of picking up the "solids" that the WC won't get.


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## yikesjason (Jul 2, 2008)

I looked into discus around here for a little bit a couple of months ago. I was not overly impressed with the Wet Spot either, but I am no expert. There just isn't a whole lot of discus around Portland it seems. There appears to be a lot more up near Seattle. Backyard Discus is one of the ones that I remember looking into. I think they are on this side of Seattle. I found them on simplydiscus. There were a couple of others up that direction. If you want to go pick out your own discus, a trip to Seattle might be worth it.


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## yikesjason (Jul 2, 2008)

Have you planted and stocked your tank yet?


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## original kuhli (Nov 28, 2006)

My system has been running for a couple years, its a similar design. A few comments:

1. I used the same style float switches from autotopoff.com, after a year and a half one finally gummed up and stuck. All that happens with my system when that occurs is that the tank will refuse to fill. I covered my sensors with loose tea filters that look something like this:http://baldmountaincoffee.com/Merchant2/graphics/00000001/sized/FULL/00002131.jpg. I'm not 100% certain whether its a good idea or not. I'd suggest considering some sort of guard from snails/plant debris blocking your floats.

2. I'm not sure what type of solenoid you're using (lazy) but I used a diaphram type like this: http://www.madhocontrols.com/solenoid_valve_lar.jpg. The problem I had with it was under unusual circumstances but basically I was messing around backflushing my filter and a tiny piece of carbon stopped the diaphram from sealing completely. 

The result was the tank kept draining, thus it kept filling. At that point I didn't have a thermostatic valve in place and the inlet water was cold (small volumes didn't matter). Consequentially some fish got very cold, some didn't make it. Two design changes were required. First a thermostatic valve, the best I could find was like you found, limited to 90 deg F or so. A bit warm and still an issue if the tank were unattended for long periods but better than freezing the fish out! And the second I did not implement: limiting the length of a fill cycle with a timer program. I really think this is an important one to avoid lots of potential damage.

The post with the setup is here, not as detailed as yours (which is the best setup I've seen to date!)
http://www.plantedtank.net/forums/g...ikka-updated-photos-before-after-replant.html


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## PDX-PLT (Feb 14, 2007)

yikesjason said:


> Have you planted and stocked your tank yet?


Stocked yes. But it's been a stressful experience, LOL. The fish looked great initially but started to go downhill. In order to try to fix things I ended up taking out the wood and sand and going bare bottom; it didn't help at all. I left on a trip to Europe last Monday (I'm still here), and the fish looked they were a death's door: based on their symptoms I treated for parasites but it didn't help. As a shot-in-the-dark last resort I started a treatment of broad spectrum antibiotics the evening before I left and asked the family to keep it up. Fortunately that worked; my family says the fish are now like when we first got them. I suspect they got sick from a bad food mix we were feeding them; thankfully they're all eating Color Bits now so we don't need to bother with a homemade mix again. 'can't wait to get home and see them.


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## yikesjason (Jul 2, 2008)

What did you end up stocking your tank with?


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## PDX-PLT (Feb 14, 2007)

Right now, it's just the 7 4" discus by themselves.


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## plantbrain (Dec 15, 2003)

We used similar lines for the warm water on a semi automated refill.
I added a temp gauge and set it for 81F.

This goes to a post carbon filter with 40lbs of AC in it and then the tank.

Drain is a simple solenoid and refill is a auto float.

Problem is that the drain is much faster than the refill.
But it's semi automated, I just drain and the tank manually, then refill, no timers etc associated.

If you want, using smaller hard plastic RO type line for drain and refill can be done much simpler and in line with the canister filters. The drain and refill is slower, there more mixing refill/flushed water, but install is much less complicated. 

Solenoid for the drain only, auto float (dual for redundancy) for refill from the hot/cold water system. You can even use the cold water if there's a decent water heater in the tank and the refill rate is slow/use small % water changes.

You still have no chlorine removal however in those schematics.

The little filter in the laundry room does not look like it can do much more than filter mechanical stuff. I'd add a dual 9.75" GAC or solid block filter and run the refill slow.

With smaller hard plastic line, it's very easy to work with, trade off is slow refill/drain. If you go large drain/fill pipe, then it seems to work to run it semi automated, turn a valve to drain 50% of the tank, turn another to refill.

Very little motivation required.
Low chance of disaster also.

It can be done either way there with the set up you have.
I'm still a semi automated person, I cannot afford to flood the places no matter what.



Regards, 
Tom Barr


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## PDX-PLT (Feb 14, 2007)

Yes the strainer is just for sediment, to ensure that no particles could jam a valve.

The water is from a private well; no chlorine or any organic compounds that would be removed by a GAC filter, so there'd be no point.


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