# Automatic Water Change System Design



## RedMoon424 (Mar 14, 2013)

This is my design I came up with after looking through many others ideas/suggestions. 

I am planning to buy a 180gal or larger tank to implement this on. 

Please feel free to input your ideas for improvement or enlighten me as to why this might not work.


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## RedMoon424 (Mar 14, 2013)

To better explain the design schematic, I thought I should add some description of what I have going on in there.
*
AUTO TOP-OFF:*
In the upper left of the diagram, we have an auto top-off. I plan to run a small water line from a nearby bathroom, or through the attic from the garage. 
When the water drops, the mechanical float valve will open, filling the tank back up. when water rises, the mechanical float valve will close, turning water off. 
If this valve fails, I have an electric float switch set a little higher in the tank, if the water rises it will raise this switch setting off an alarm and powering a normally open(NO) solenoid, thereby closing it. (the alarm will continue to sound until I take care of issue). The T-ball valve is in case of this scenario so that I may close off the water line manually. 
Also, I want to point out that in this design the water coming into the tank goes through a canister/Biological filter before actually getting fed to the tank. This is my attempt to help minimize any chemical, or water issues that may be coming from the water source (in my case, I have been topping off my 30 gal with straight tap water for years now with zero issues, so I do not see any issue with running it directly. I do know that some people have chlorine, or chloramines in their water, in which case a water aging tank may be necessary)

*AUTO WATER DRAIN:*
This is the part of this design that makes this automatic water change possible. As you see in the bottom right of this schematic, there is a drain pipe that drains the water to a pump when the 2 normally closed (NC) solenoids are opened by a timer. This timer also simultaneously gives power to the pump. 
There are 2 solenoids so that in the event of one of them failing the other will still work. Also, since these are both (NC) solenoids, in the event of a power outage, there is no chance of water draining out of the tank. instead they would just remain closed and we just wouldn't get our water change. 
The two ball valves are to allow manual shutoff of drain, and to act as a flow regulator (close it to drain at desired speed).
Since the Auto top-off has unlimited water supply, once the drain turns off, the auto top-off will do its job and fill er' back up. 

*RISKS/SAFETIES:*
As far as I can forsee there is relatively low risk in setting up a system in this way. I have Identified that the only way for this to cause a flood is if the Auto Top off valve fails AND the secondary switch fails (like if power was out). but that is a relatively acceptable risk IMO. 

And there is no risk of over-draining your tank because the drain pipe is set to the MAX drain level you wish to allow. (if timer hasn't shut off by time water drops below drain pipe height, it will just suck air until timer shuts off - one reason you need a pump that is ok to be run dry for a few minutes)

This design requires water to be pumped out of system, in my case it will be up a 12ft wall (behind drywall) through the attic, and back out to the garage tied into my laundry tub sink, or out of the attic somewhere else (Not entirely sure how I am going to run this line yet). Advice welcome here.

I want to point out here that the risk of a siphon completely draining the tank is zero. In the event that both solenoid valves are broken in the open position (almost impossible situation), and somehow a siphon was created, it could only drain to the level of the drain pipe (which we have set to the MAX water change level). This would save the fish, and would act as an indicator that both solenoid valves are bad. Fail-safe. also, it would not be draining into your living room, but instead be drained to wherever you have it tied into your plumbing.

One major risk that I have identified is the fact that a water line is being run through the attic. I personally live in florida, so the threat of freezing is practically zero, but if you live in a place that freezes, you must take that into account when planning your water supply line. I have heard that running a PEX line through the attic is fairly safe because it is resistant to breaking due to freezing or heat. (any confirmation on that would be nice)

*BENEFITS:*
Never have to touch a water bucket for top-off or water change again.
Can set mini-water changes multiple times a week instead of large ones.

SO, there is my Idea, Please let me know what you all think. I look forward to your comments


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## Redhead305 (May 30, 2012)

im from florida too is your tap water's ph suitable im pretty close to the atlantic basically 5min away so my ph tends to be aroung 7.5 on avg. also the chlorine if you have a rodi system then you're set but does you're tap have chlorine present


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## RedMoon424 (Mar 14, 2013)

Redhead305, you make a great point about this design being dependent upon acceptable water parameters coming into the tank. 

You mentioned your tap water PH being about 7.5 in your area. Mine is about the same, but this is acceptable for me because I am keeping Mbuna/Malawian cichlids who actually prefer a higher PH of between 7.5 - 8.2. (my understanding, please feel free to correct of I am mistaken on that). My plan is to use an aragonite sand bed, and either a limestone or other rock for decoration/hiding, which should act to raise/buffer the PH to within the desired ranges. (looking for suggestions on inexpensive rock to use).

You mentioned chlorine and chlorimines. This is something that I may need to take a closer look at. In the past 2+ years I have used untreated tap water for my 30g tank with no issues. However I usually do <10% water changes, so if there are traces of chlorine/chlorimines, it disperses and hasn't harmed my fish. 

This new system has the capability to do more frequent water changes and I can easily see how even a little amount of chlorine could become a bigger issue. 
To address this issue, a water aging tank can be implemented, or as you suggested, an RODI system (which I have no experience with, and cost a lot). Also I have read that RODI units are not effective in line with an auto top off because of the constant on/off which wears it down much faster or something? 

In any case you make very valid points Redhead305, that is something I need to look at a little closer before I waste money/time running a water line through my attic/walls. 

Thanks


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## Redhead305 (May 30, 2012)

no problem redmoon424 and you are correct about the ph i personally would avoid the argonite sand bed and go for a basic silca sand bed due to the fact if your water is naturally higher in ph like mine it will only push it more. what you could use for stone is simple paving stones from a hardware store i.e home depot and lowes. ive done it before on a smaller setup where i purchased a ton of stones chipped them with a hammer and bonded them together to make artificial caves and ledges for them of course with a 180 that might be a bit time wise out of the option but its an idea. i've never used a water aging system but i have seen the idea work. my job has a fish system with the same concept to top of the tanks and do water changes.


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