# Automatic water change (tank drain)



## mids1999 (Feb 22, 2007)

Does anyone have any ideas on how I could setup the drain part of an automatic water change system?

Here is what I am planning.

I am planning to use my Apex (from my reef tank) a solenoid on the in line, and 12v float switches.

I am going to set one float switch as a low water level control and one as a high level control.

I will be using a solenoid on the clean water leg of my R/O system controled by the Apex to fill the tank.an

Where I am sort of confused on how to drain the tank.

What I have planned so far is to use the second float switch as an indicator for the Apex to stop draining the tank.

What I need help on is the mechanical part of the drain system.
Anyone have any ideas?

Once the water is out of the tank, I have a floor drain right next to the tank.

Tank is a perfecto 75g w/ 1 megaflow overflow.


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## geeks_15 (Dec 9, 2006)

I'm not sure if this would work, because I'm don't completely understand how your setup works.

Could you just run fresh water into the aquarium and allow water to overflow through the megaflow and down to the drain? Then you wouldn't need the float valves. 

I've been thinking about doing this with my tank to make a constant automatic water change system.


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## TAB (Feb 7, 2009)

adding water to ta tank so it will overflow to a drain is a flood waiting to happen.


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## geeks_15 (Dec 9, 2006)

> adding water to ta tank so it will overflow to a drain is a flood waiting to happen.


Why?


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## TAB (Feb 7, 2009)

if that drain gets cloged even a little you are in trouble. With a planted tank the risk goes way up do to leafs and the like getting stuck in the drain.


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## geeks_15 (Dec 9, 2006)

I'm currently running a sump that is basically the same thing. Water overflows to the sump. A pump pumps the water back up to the tank. If the outflow were to get plugged it would cause a flood. I think running water to a drain would be basically the same. The difference I guess is that if you have constant water running into the tank and get a clog you will have a much larger flood if you are gone or asleep. 

I was thinking of setting up a solenoid on the water inflow with a timer and only drip water for a set time period. For example, a 55 gallon per day RO unit could be set to run long enough to produce 10 gallons per day (into my 75 gallon tank). That way I do about a 50% automatic water change each week. The water overflows to my sink. So instead of a sump, I have an automatic water change. Check my journal (linked below) for pictures of my setup.

BTW, I'm not trying to hijack your thread, I'm just trying to present some ideas.


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## Zapins (Jul 28, 2004)

I wrote a DIY thread about this a while back, read through it it should help answer your questions (I've got pics in there too).

http://www.aquaticplantcentral.com/...automatic-water-change-system-design-diy.html

But in a nutshell: you can't connect your aquarium drain to the house drain system, it isn't legal (the house drainage system isn't designed to handle more water then an average household does so it could overflow the system). The most practical way of getting rid of waste water is to use it as "wash water" draining it into your garden, say for example, the shrubbery or woods near your house is a legally acceptable way of getting rid of the water, as long as it doesn't pool, run into a neighbor's yard, and isn't closer then 10 feet from your house foundation. You could alternatively dig a dry well and pump the water in there, or dig a mini-leach field, but these are much more expensive then draining it off into the bushes. I checked out these options with my local health department and they Okay-ed it for my area (Hamden, CT), though laws will differ from state to state, you can just call up your town's health department and have a chat with them about your options.


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## TAB (Feb 7, 2009)

geeks_15 said:


> I'm currently running a sump that is basically the same thing. Water overflows to the sump. A pump pumps the water back up to the tank. If the outflow were to get plugged it would cause a flood. I think running water to a drain would be basically the same. The difference I guess is that if you have constant water running into the tank and get a clog you will have a much larger flood if you are gone or asleep.
> 
> I was thinking of setting up a solenoid on the water inflow with a timer and only drip water for a set time period. For example, a 55 gallon per day RO unit could be set to run long enough to produce 10 gallons per day (into my 75 gallon tank). That way I do about a 50% automatic water change each week. The water overflows to my sink. So instead of a sump, I have an automatic water change. Check my journal (linked below) for pictures of my setup.
> 
> BTW, I'm not trying to hijack your thread, I'm just trying to present some ideas.


while yes that is true, the ammount of water you can pump into your tank is not alot. Doing a wc of say 25% on a tank a larger tank and now your talking 50+ gallons of water.

for top off, I'd recomend it going into a containter, for several reasons.
1 the 1st few gallons of water out of a RO, are not the best.
2 a failure in the membrain does not go directly into the tank
3 flood

those are just the 1st 3 that come to mind.


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## geeks_15 (Dec 9, 2006)

I've actually looked through your set up (that you linked to) before. It looks great.

Interesting, it is illegal to drain aquarium water into the household drain? 

In my proposed scenario I'm sending approximately 10 gallons of water per day to the drain. That is about the equivalent of a 5 minute shower or doing one load of laundry.

Most aquarium owners don't collect their water like you propose, and anyone with a large aquarium would be sending a decent percentage of water down the drain vs. the average household usage with each water change automatic or not. I've never heard this before and I doubt most aquarium keepers would even think about it. I didn't.

Also, I noticed TAB had the same opinion of your setup that he posted in this thread .


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## TAB (Feb 7, 2009)

there is nothing at the national level that says you can't hook it up to the drain. You would have to do it like a drain for a washing machine. trap, clean out, proper venting. 

Now your local and/or state codes may say something else.

I would not recomend it if your a septic system.


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## Zapins (Jul 28, 2004)

geeks_15 said:


> Interesting, it is illegal to drain aquarium water into the household drain?
> 
> In my proposed scenario I'm sending approximately 10 gallons of water per day to the drain. That is about the equivalent of a 5 minute shower or doing one load of laundry.


Heh, I tried the same argument with my local health department but they told me that while this may be the case, legally speaking, in my area it isn't allowed. I think most places will have the same view since the reasons behind not allowing it to happen are the same everywhere. It is super inconvenient for sure, but unfortunately that is the way it goes.

Its nearly as easy to just have the water pumped outside to water the garden so that is probably your best and safest bet if you live in a home and not an apartment or something. If you have an apartment, you might be able to connect it to the gutter on the outside of your house.


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## davemonkey (Mar 29, 2008)

I'm not trying to be an advocate for breaking laws or anything, and I certainly agree that used aquarium water is better placed in the flower beds or shrubs, but how exactly would the city or state know if you dump your tank water down the drain? 

-Dave


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## TAB (Feb 7, 2009)

davemonkey said:


> I'm not trying to be an advocate for breaking laws or anything, and I certainly agree that used aquarium water is better placed in the flower beds or shrubs, but how exactly would the city or state know if you dump your tank water down the drain?
> 
> -Dave


you would be amazed... building inspectors/ code enforcment tend to find things that they were not looking for. I know many people that have been nailed for things in thier back yard becuase some one close by had a inspector over for something. Every thing from draining pools illegally to sheds that too large/too close.


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## Zapins (Jul 28, 2004)

Yep exactly as TAB said. Building inspectors. We actually have a home inspector scheduled to come and inspect our house for figuring out taxes based on house size soon, so I couldn't break the law and get away with it


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## mids1999 (Feb 22, 2007)

I was actually planning to drain directly outside into my garden which is right on the other side of a thin wall that I am planning to put another hole into. (I already have one in there for my chillers exhaust.)
I am planning 3x 10% water changes per week. 7.5gal each time. I am sure that I use alot more than that when I water the garden.

Thanks for all the great replies so far.


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## mids1999 (Feb 22, 2007)

I was actually planning to drain directly outside into my garden which is right on the other side of a thin wall that I am planning to put another hole into. (I already have one in there for my chillers exhaust.)
I am planning 3x 10% water changes per week. 7.5gal each time. I am sure that I use alot more than that when I water the garden.

Would this NC solenoid work to stop the water from flowing out? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300373428176 Or is there some reason that it would not work?

I am thinking about using a powerhead (like an aquaclear 70) to pump the water out and opening the solenoid valve to allow the water to flow.
When the second (lower) switch sends the water level signal, the pump should stop and the solenoid will re-close.


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## TAB (Feb 7, 2009)

soleniods have been known to fail. if your looking for a mechainic valve I would recomend going with a motorised ball valve. they are not cheap, but alot more reliable.


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## Zapins (Jul 28, 2004)

You could do what TAB said, or you could drain the water into a bucket first, put some float valves (more then 1 in case 1 fails) in the bucket near the top and wire these to a relay and then the relay controls a solenoid on the fresh water pipe into the fish tank. If the water level ever rises too high in the waste water bucket due to a failed pump or a clogged waste tube then the rising water will trigger the float valve which tells the relay to shut off the fresh water. Thus, no more water will flow into the tank, and into the waste water bucket and there will be no flood. This is a negative feedback solution which should add an extra layer of reliability to your system since you definitely do NOT want to deal with a flood.

I used the system I described above in my WC system and its worked for the past 3 months with no problems (I've thoroughly tested every possible place along the way that water could cause a problem and everything functions very well since there are multiple checks and balances).


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## TAB (Feb 7, 2009)

float switchs can and do fail. I would not recomend then to "stop" water in a container.

Even when I was using a ATO system, my float swtichs went to a timer. so when the float switch triped, it would only turn on the pump for a short peroid of time.


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## Zapins (Jul 28, 2004)

That is what I was worried about and why I built in 2 float switches in case one fails. You could build in more then 2 float switches (10+ if you'd like), if any one of them is triggered they cut the power to the solenoid. Repetition definitely helps avoid disasters!

I've got my system on a timer as well, but I think it is set up differently from your system TAB. I've got it so that the system only pumps water for 4-5 hours a day. This limits the amount of damage a catastrophic failure in the float switches would cause since the system. The float switches are always on though, just the incoming water is on a timer.


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## mids1999 (Feb 22, 2007)

I was just thinking.

I have the megaflow overflow (which is not siphon operated) in the case that a solenoid or float switch fails. So worst case I would either end up with a burnt out power head or water running into the tank and out the overflow.


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## Zabman14u (Jun 20, 2009)

id hate to revert the topic back to the legal aspect again but what if you would run the drain into a sump pump if you have one? the sump water is supposed to be just rain water, uncontrolled except by nature and is supposed to be pumped out into the storm sewer or tile. i have been curious on this topic myself.


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## TAB (Feb 7, 2009)

pumping tank water into a storm drain is a very bad idea.

not only will it get you in big trouble, you are also introducing non native plants/ animals directly into the local water ways.


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## mids1999 (Feb 22, 2007)

I have my system running for a week now and so far, so good.

The tank drains approx 15g into my garden through a hole in my wall via solenoid valve and pump. (the solenoid valve does not allow water to flow without the added pressure of the pump.)

Then the tank tops itself off from my ro system approx 10 minutes later.

I also added y in the line that goes to the tanks overflow so that if the top off solenoid was to get stuck on, then the water would just go up over the overflow and out through the wall and into my garden.

Now I just have to find some way to warm the water up before adding it to the tank.
The temp currently drops about 6F when filling.


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