# Automatic Water Changes



## Raul-7 (Feb 4, 2004)

We all tend to forget to do regular WC's, but it does become especially in such cases as breeder tanks. I've thought of a solution, but I'm not quite sure if it's practical. Here's my idea: Use a mechanical pump that actually sucks/pulls water from the main tank (using a timer to determine how much water you want to change daily) and deposits in a empty bucket, drain etc. Then using another pump to pull water from a drum full of water into the main tank. It might be a good idea to use the same power pump for both applications and maybe even synchronize them on the same timer. What do you think? Is it even possible?


----------



## turbomkt (Mar 31, 2004)

Raul,
The only way I can think of to be sure you don't suck out too much/little, or return too much/little, is with float valves. Otherwise, even with the same size pump on both sides...are they equal? Are the tank and the drum going to be at the same level? There's this issue with water at different head heights that bothers me.

--Mike


----------



## czado (May 26, 2005)

I like the idea of a float switch for the input pump, as it can top off the tank as water evaporates. Pump and head height difference shouldn't matter since you're draining then refilling. Here's a nice hobbyist water change system howto from TomK2 of AA: http://home.comcast.net/~tomstank/tomstank_files/page0015.htm


----------



## turbomkt (Mar 31, 2004)

I was worried about different head heights because it sounded like he wanted to use a timer without a float switch.

--Mike


----------



## czado (May 26, 2005)

If its one timer for both pumps (they're operating concurrently), you're certainly right, Mike. If one timer turns on, then off, the drain pump, then another timer turns on, then off, the input pump, the pumps and head height shouldn't matter, provided the on time of each is correct.


----------



## Fosty (Jun 6, 2004)

It's a great idea, but you would have to be very careful with it. You would have to watch it very carefully because one small screwup and you can have tons of water all over your floor (I know from experience). Even once the system is perfectly timed, there are things that can go wrong and cause a lot of trouble. Its a great idea, but I would aproach it cautiously.

Good Luck!


----------



## dennis (Mar 1, 2004)

How do you keep the drain pump from creating a siphon and continously draining the tank? Is there some kind of solenoid valve in the drain line?


----------



## czado (May 26, 2005)

Check out Tom's pipe within a pipe siphon break (last paragraph) in link above. Out line from the pump is fitted into a larger pipe above the tank -- in his case drain is going to the sink (why use a bucket). The larger pipe prevents spraying at this point. Solenoid is clever - placed low enough, one wouldn't even need the out pump, and can just use the siphon to drain water?


----------



## Raul-7 (Feb 4, 2004)

I would need a solenoid valve, but what happens if the power goes out? And could the valve be used to start/end the siphon? How would I position the float valve to make, for example, start the in-pump when the tank level reaches a level below 6"?

I'm thinking I would time the out-pump to see how fast it sucks the amount of water I change daily, and then time the in-pump to see how fast it pushes the same amount. And use different timers for both operations.


----------



## turbomkt (Mar 31, 2004)

Raul-7 said:


> How would I position the float valve to make, for example, start the in-pump when the tank level reaches a level below 6"?


 Ever seen the inside of a toilet? Same idea but not necessarily as big (Electronic vs. mechanical float switch).



Raul-7 said:


> I'm thinking I would time the out-pump to see how fast it sucks the amount of water I change daily, and then time the in-pump to see how fast it pushes the same amount. And use different timers for both operations.


 The only way this will work 100% is if the water level in the supply drum is at the same point every time the fill starts. Otherwise, you'll end up under-filling the tank. Then, when your drain line goes, it will take the water level lower than planned...and it all becomes a vicious cycle.

I could be wrong...

--Mike


----------



## czado (May 26, 2005)

I _think_ if the solenoid valve is lower than the pipe's entry in the main tank, it should keep siphon. The pipe will remain filled with water to the valve, and once the valve opens, water would drain to your bucket. In case of power outtage, you can build in redundancy by having the drain line high enough in the tank to prevent too much water draining out. (Many sumpers do this with their return lines.)

More DIY links 

Float switches:
http://www.kingvinnie.com/aquaria/diy/links_page.asp?cat=18
Water top-off systems:
http://www.kingvinnie.com/aquaria/diy/links_page.asp?cat=16


----------



## Raul-7 (Feb 4, 2004)

I do plan on making the pipe removing water out of the tank short enough to suck a maximum of 50% of the tank water just incase something goes wrong. But I still have a question about the float valve, does it turn on the pump as soon as it detects any decrease in water level or only when the "booey" reaches all the way till the end? Because a float valve would be pointless if as soon as the siphon starts removing water, the pump turns on and keeps adding water.


----------



## czado (May 26, 2005)

I've never messed with a float switch and wish I could help, but the working links at King Vinnie's show a switch that turns on whereever it trips (seems easy to simply mount this as low in your aquarium as needed). I think the possible issue is the switch would turn off before reaching the top. I'm sure you can figure out a way to have a longer throw, so it doesn't switch on until the water line is 6" from the top, and doesn't switch off until it, say, fills up 5". 

A suggestion: how about putting the float switch and in pump on a timer? You use the float switch to turn off the pump 1" from the top (upside down float switch as I understand), so you ensure no overflow. Timer only ensures that the float switch and in pump stay off during the drain pump or solenoid's time. You keep water top off. Just a thought experiment with no applied experience to draw from, but I don't see why it won't work.


----------



## Raul-7 (Feb 4, 2004)

Nice suggestion. But why use an upside down float switch?

I was thinking: siphon starts via valve via timer, and during that time I use another timer to ensure the float switch doesn't trigger the pump to turn on during the siphon "cycle". Then after a minute after the siphon, the timer turns on triggering the float switch to turn on the pump. How does that sound?


----------



## gnatster (Mar 6, 2004)

> I was thinking: siphon starts via valve via timer, and during that time I use another timer to ensure the float switch doesn't trigger the pump to turn on during the siphon "cycle". Then after a minute after the siphon, the timer turns on triggering the float switch to turn on the pump. How does that sound?


Sounds like a flood, flopping fish in dry tank and mess just waiting to happen. At work right now so can't give this the thought it needs. Try thinking KISS method, cause the more complications the more failure points.


----------



## turbomkt (Mar 31, 2004)

I don't think it's a bad idea, assuming a few things. First is that the siphon tube is only half way down the tank. Second is that the fill doesn't happen until the draining is done. Once again it's a timing issue.

Odd thought...will you be able to drill the tank for the drain tube?

I'll be honest, my experience with float valves is a little more primitive...but on a grand scale. I was responsible for a 3000 gallon CHT tank (portable septic tank) that used three float switches to control the pump. One turned the pump on and the other turned it off. But in this case the pump was the drain and fill was whatever the ship put in.

I'll agree with gnatster on keeping it simple, though. Whatever the most basic set up is, I'd go with that.

I'll admit I haven't looked at kingvinnie's pages yet, so I'll come back later


----------



## czado (May 26, 2005)

Raul,

Float switch is with normal orientation at the top of the tank? Sounds good to me. Upside down switch thought was for redundancy to kill the in pump, but my thinking was upside down  You keep redundancy with the normal orientation I think.


----------



## turbomkt (Mar 31, 2004)

This is the important quote:


> _It can be made to be normally open or normally closed by flipping the little float over. This means that this top-off can be used as a overflow shut off too. _


If you're using an automatic/solenoid valve on the drain side, a float switch down at the cut off point could be used to close the valve. Lots of possibilities.

Remind us again...how complicated are you trying to go?


----------



## Raul-7 (Feb 4, 2004)

Thanks for the suggestions!

So we finally found a practical solution. But wait, I need two float valves; one to turn the pump on, and the other to turn it off. I thought it does both? 

And no I don't plan on getting too complicated.


----------



## turbomkt (Mar 31, 2004)

Just to make sure we're on the same page...what do you see as the solution right now? And then we can take that and make sure it's feasible.


----------



## stcyrwm (Apr 20, 2005)

The real trick to this system would be safely filling the tank. Draining is easy - you setup a syphon with a normally closed solenoid on a timer and set the timer to the amount you want to drain. If anything goes wrong you drain to the bottom of outlet pipe and lose syphon - no big deal. On the fill side it is trickier because fill valves and float valves fail and then you have a lot of water running all over the place. The only way I could see to safely do this would be to have an overflow pipe just like they do in a toilet which means you'd have to have a drilled tank. This way timer would turm pump on to fill and float valve would turn it off. If something went wrong water would go out overflow - again no big deal. You'd also have to have a bucket to pump out of that filled automatically and then sat long enough, to off gas any chloramines. This bucket could be hard plumbed and would also need an overflow. 

The KISS alternative to having the drilled tank is to set this all up and not have it be set up on timers. Instead of a solenoid you just have a valve that you open to syphon to a drain. Shut it off when it's drained to the level you want. Then flick a switch and pump comes on to fill tank. All automatic and no worries about anything going wrong because you are there to monitor. Just don't answer the phone ;-) .

Good Luck, Bill 
VT Plumbers License #PM-3364


----------



## plantbrain (Jan 23, 2004)

If you fill it slowly and have a sump, then a float switch is all that is needed along with a small pump and timer for draining.

Several of us use these in SFBAAPS.

They set it to chabnge 30% of the water 2x a week.
They have been running for some years now.

I prefer a hard plumbed system, a simple valve for fill and a simple valve for the drain.

I drain as much as I want by turning a valve. I work on the tank. and when the levels ios low enough I shut it off, then turn the fill valve.

You can use a pump to drain the water to a non siphonable location.
You can also fill the tank from a trash can or or other container etc using a pump.

I prefer this since it allows me time to work on the tank and prune, clean etc while I'm waiting for the refill.

I'll work 1/2 a tank each week.
This is the maximal time efficiency ansd consistency along with safety.

If you wonder off anmd forget to turn the tank fill off, then that's abiout the only way you can mess this up.

Which ain't bad since everyone can and likely has done that already.
Then it's not the system, it's you

I've done 3 such systems and several auto changers now.
I'm old fashioned I suppose, I still like the valves for the drain/fill.

You can also set the mixing by adding two valves for the hot/cold water and add a carbon filter prior to the tank to remove Chlorine etc. I have that on two tanks.

Regards, 
Tom Barr

www.BarrReport.com


----------



## Raul-7 (Feb 4, 2004)

I just contacted Paul at www.autotopoff.com and he said what I'm looking for is a double-switch-latching float switch [try saying that in one catch ]. This type of switch has two switches, one at the bottom and one at the top; the lower turns it on and the top turns it off, and both can be moved farther apart to control when I want the pump to go on and off. The only problem is that it comes at a heafty price at around $60.

As for the drilling factor, how big of a hole should I use? I'm thinking 3/4" or 1". Should I go with vinyl tubing or PVC?


----------



## czado (May 26, 2005)

Are you ditching the timer for in pump entirely with two float switches? Just curious.

Re drilling: If the tank is established and glass its a somewhat tricky procedure, and people smarter than me think drilling an established tank is a bad idea. Here's pics and instructions of how I did mine though, if interested  You'll need PVC and O-rings for the bulkhead, and you'll probably want to try a side if you do this since the bottom is likely tempered glass. PVC is nice for piping since its easier to find ways to support the weight with redundance, and flex tubing takes longer since you need to adhere it to the bulkhead. I think you should consider a regular overflow box if you want redundancy on the drain, though. This can simply be two Lee breeder boxes, a J tube, and two small baffles to keep siphon, and plans abound on the net. Chuck Gadd has nice howto: http://www.csd.net/~cgadd/aqua/overflow.htm


----------



## czado (May 26, 2005)

Hey. For refill supply, how about airtight holding tank above the main, with a hose at max water level? As soon as water level is above the pipe entry, water stops draining. I just tested this with a bottle of water and a coffee mug -- also see Water Bridge. You could use a solenoid or whatever on that line to keep it from refilling while draining the tank == pumpless autowater change system. Still need to refill holding tank, of course.

It could also be neat to add proper macro solution to a holding tank, for someone who uses a low water change method: topoff with fertilizer rich water.


----------



## Xzap (Jul 5, 2005)

*Evaporation Compensation Sysytem*

I made this yesterday for $7.75 in about 15 minutes. I call it Xzap's ECS. As czado said, it would also make a great dosing chamber 

It's gravity fed and in theory it will fill the tank with water due to evaporation to whatever desired level you set it. And that's no more than where you place the bottom of the input tube. when the tank's watre level reaches the bottom of the input tube, the water will stop draining into the tank. This particular pitcher I used isn't 100% air tight, so I use the off/on valve.

Thx,

dave


----------



## norm3000 (Aug 28, 2005)

Hi all. I've worked on an automatic water change system for my discus tank. Have it all assembled but don't have it running on the timers (I had one "close call" and now have cold feet). Right now I just have it so that I push one button to drain the tank, one to fill it and then one to fill the reservoir half way with tap water (I mix 50/50 RO and Tap).

Here's a diagram I put together a while ago showing all of the components:

http://www.anklebiters.org/norm/images/AWC.gif

This is the original plan, although again I don't have the timers running:

1) Timer turns on a submersed pump in the tank and drains 40% of the water (or whatever you like). The pump is attached to PVC and hangs 40% of the way down so it can't drain more than that.

2) Submersed pump in the resevoir fills the tank back up. This is turned on by a timer but a float switch in the main tank turns it off. This insures no overfilling.

3) A solenoid valve (sprinkler valve) is powered on by a timer and fills the reservoir back up to 50%. Again a float switch turns the solenoid valve off to insure no overfilling.

4) RO unit fills the reservoir the rest of the way and a float valve made specifically for the unit (Kent Marine) shuts it off when it is full.

The reservoir is heated with a submersible heater and sits for at least 24 hours after being filled 50% with the tap water so the cholorine will evaporate.

The close call I had was that the 3/4" hose adapter to my RO unit popped of. Lucklily I was home and turned off the hose right away. But if I had been at work I would have had a hose running full blast in my living room all day. Somehow the plastic fitting expanded under the pressure of the tap water and just popped off. I've replaced it with a brass fitting now.

So I gave up on completely automating it but just have 3 switches to control it now. I find this is easy enough that I do my water changes regularly.

btw, I ordered my float switches from here: http://www.floatswitches.net/
The side looks a little cheap but I had no problems at all with them.


----------



## urville (Sep 20, 2004)

This is hands down the best water change system i have ever seen

http://www.cichlid-forum.com/articles/auto_water_changer.php


----------



## simonbrown403 (Sep 3, 2005)

heres hoe some else did it
http://www.simplydiscus.com/forum/showthread.php?t=43949


----------



## ranmasatome (Aug 5, 2005)

That is one HELL of a system! really neat.! having integrated solenoid valves to have it fully automated will be so wicked!


----------



## plantbrain (Jan 23, 2004)

The option I like that is very safe is the hard plumb fill and drain lines.

Open a valve by hand, drain. 
Close it to stop the drain.
Open another fill valve to fill.

Done.

While drain/fill: you prune.
Works quite fast, not much work.

Even a friend with little experience can do it.
Add 2 dosing pumps and then you have very little work other than weekly easy tending/filter cleaning etc.

Regards, 
Tom Barr


----------



## Zapins (Jul 28, 2004)

i have some of my own ideas about water change systems, but they arent quite ready to share. i do have 1 question though that might help the design process:

1) does anyone know of a heating device that would heat water as it comes into the tank? (i.e. an inline heater that would heat the water to 78F w/o a reservoir drum)


----------



## stcyrwm (Apr 20, 2005)

Zapins said:


> i have some of my own ideas about water change systems, but they arent quite ready to share. i do have 1 question though that might help the design process:
> 
> 1) does anyone know of a heating device that would heat water as it comes into the tank? (i.e. an inline heater that would heat the water to 78F w/o a reservoir drum)


You could try an electric on demand water heater like the one here: http://www.plumbingsupply.com/instant_flow_water_heaters.html.
They also make a little less expensive ones that hold a gallon or two of water.


----------



## czado (May 26, 2005)

Another schematic/plans.

http://aquariumadvice.com/viewtopic.php?t=61387


----------



## DarrenJThomas (Sep 13, 2005)

I have a larger community tank that also contains discus. I have an overflow box and sump filter on the system. As my water changes can be as much as 200 lts at a time and I use RO water i have devised a way to continually introduce new water over a 24 hr (or forever) basis.

Inside the sump i have a pipe that looks much like the old washing machine sink plugs that allow you to re use your water. As the tank is filled with new water existing tank water siphons out of the pipe. Hence a continual flushing of water.


----------

