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Automatic Water Change System


dandy7200

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I get a lot of questions about this so I thought I would put together a thread for it so I don't have to type it out every time :biggrin:

 

I change 1/2% daily. Well actually I am usually having my morning coffee when the water is being changed by the aquacontroller. This is a ton cheaper that the litermeter setup and more reliable that the Calfo system.

 

Works like this:

 

I put in a bulkhead at the top part of my sump with a elbow. This is plumbed to a floor drain. I filled the system up completely with water until water started to flow down the drain. This is the MAX water I can have in the system with the PUMPS OFF.

 

185084432_72626eac37_o.jpg

 

Then I turned my return pump back on. The level of water in the sump is now at the MAX level and I keep it at that exact point with my auto top off:

 

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Salt water tank with pump plumbed to refugium. This tank has been upgraded to hold 30 gallons. Every morning this pump comes on for 1 minute putting about 1/2 gallon of new saltwater in the system.

 

185084426_9a7d4a17cd_o.jpg

 

Water then circulates in the tank for 15 minutes.

 

I took this picture with 4 gallons of EXTRA water running in the system to exaggerate the illustration but that top piece of blue tape is where 1/2 gallon puts the sump level. Remember this is MORE water than the system can handle.

 

185084429_1fb9a456a8_o.jpg

 

After the water has circulated then the return pump is cut off by the aquacontroller for 5 minutes. Any ADDITIONAL water in the system (read what ever the amount that was pumped in 15 minutes previously) is overflowed out the drain elbow.

 

185084432_72626eac37_o.jpg

 

The return pump is then turned back on and about a 1/2 hour later the lights turn on.

 

Heres the controller code:

 

WCP= water change pump

PM1= return pump

 

If Time > 10:40 Then WCP ON

If Time > 10:41 Then WCP OFF

If Time > 10:56 Then PM1 OFF

If Time > 11:01 Then PM1 ON

 

 

This system is scalable so at any time I can just let the saltwater pump run longer for a larger water change. I change about 15% of my total water volume a month and have never seen the need to do more that that. I really believe that by changing small amounts frequently it is better for the system than larger changes and you are allowed to change less water than is normally required. This tank has been on this system since day one and I have never detected No3 in the water nor do I have any algae growing in the tank or any other nutrient related issues and believe this is the key.

 

One question I get regularly is "Are you changing some of the water you just put in?". Yes but it is so insignificant it makes no difference to me. If I changed 1 gallon a day on a 100 gallon system, 1/100th of a gallon that went down the drain would be new water or 1.25 ounces. I can live with that. Heck, I used to suck that much with a siphon in the old days and certainly spilled more on the floor.

 

So there you have it, my auto water change system. Feel free to ask any questions.

Edited by dandy7200
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Feel free to ask any questions.

 

Only one question comes to mind: How soon can you have it installed on my tanks? :wink:

 

Once again, nice job and thanks for posting. That setup would also help prevent overflows in the even Murphy steps in and leaves the ATO running too long then drops power unexpectedly--while no one is home to notice. Of course we know that flooded sumps are very rare in this hobby!

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I have gone through the list of gotchas on this one pretty thoroughly. It is as close to 100% safe as it gets in this hobby. The worst thing that has happened is one day I was manually overriding the pump to add a couple gallons to the system after bagging frags and then left the house for a few hours. When I came home I heard the pump sucking in the empty saltwater bucket and realized that I did a 20 gallon water change by accident. Again, if this is the worst that can happen I think I can live with that minor inconvenience :lol:

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I have to say that I have seen this in person, and it is just awesome. Dan has an amazing talent for ingenuity and creativity. I am copying this setup for my house, and hope to have it finished this weekend. Thanks for this thread Dan!

John

:cheers:

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How do you keep the salinity level in your make up water?

Does your system add the salt automatically or do you add it?

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The salt water reservoir has a loose fitting lid and a power head. Never noticed any significant salinity variations from evaporation. I do have to actually make salt water so that part is done by hand. I have a 30 gallon RODI reservoir as well and just make sure it is full the day before I want to make water.

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This is a great idea, i had a similar thought, not an automatic water changer but something similar since my tank is on the third floor there is no such thing as a floor drain for me

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  • 9 years later...
  • 2 weeks later...

How are you controlling the salt level if you are adding salt water to the system? Seems you would have your levels slowly creep up. Do you have a conductivity probe to monitor and shut down your addition of water if the levels get to high?

 

I do love the overflow drain idea! I've been thinking about this for a while and pretty sure I'm putting one in when I move.

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How are you controlling the salt level if you are adding salt water to the system? Seems you would have your levels slowly creep up. Do you have a conductivity probe to monitor and shut down your addition of water if the levels get to high?

 

I do love the overflow drain idea! I've been thinking about this for a while and pretty sure I'm putting one in when I move.

 

His tank (back then) had a regular ATO installed with fresh water. What he did in this situation was to add saltwater to his system in excess of it's "pumps off" capacity. He did this while the tank was running and then, after the new saltwater was thoroughly mixed with his tank, he turned his pumps off. This caused water to settle (and siphon) back into the sump where, because he'd installed a bulkhead up high in the sump (at the max sump level) the excess water would be pushed out of the tank and into the floor drain. Then he'd turn the main pump back on and things would return to their normal operating levels.

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Does anyone else in the club use this system or similar standard-controller based auto-water changer?

Ctenophore (Justin from Avast) was using an auto water changer system that ran every day and performed micro water changes each day. His system made use of a calibrated salinty probe, as I recall. It maintained topooff but than, during the water change, replaced it with fresh and saltwater each day to maintain salinity. 

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