DIY water changer

I don't see the benifit of complicating this with computers and pumps.... what's the point?
 
You don't need a computer or pumps, but you will at the very least need some relay logic circuits with level sensors, solenoid valves, and possibly timers utilizing gravity for flow.

You have to have something to monitor water levels for a system like this.

(20 years as an automation controls engineer)
 
I can picture a use for a float valve or two, and maybe a timer, but beyond that...? I'm really a KISS type, and not much of a teckie. I'm good at physics and DIY stuff. Please explain what all the solenoids, circuits, and sensors would do and how they work?
 
I can picture a use for a float valve or two, and maybe a timer, but beyond that...? I'm really a KISS type, and not much of a teckie. I'm good at physics and DIY stuff. Please explain what all the solenoids, circuits, and sensors would do and how they work?

sensors = float switches to detect levels

solenoids = electrically actuated valves to turn on and off flows

relay logic circuits to connect the sensors to the valves for "programming"
 
nagh, just a python and a solenoid valve with a low and high level float with a single solenoid valve would do it with 2 relays, if you were willing to push a button when it needs a change.
 
Seems like a lot of work once done it may have just been worth it to carry those 5gal buckets.

Not a lot of work at all....and when you're dealing with 100g tanks and larger with weekly, semiweekly, or daily water changes.....5g buckets are no way to go. You can put together an Auto WC system in less time than it takes to do ONE 50% WC on a 100g tank using a 5g bucket.


I'm putting an Auto WC on my 120. All you need is a timer, couple of relays, 2 solenoids, and a float switch....and some DIY-fu. Wire the relays to the timers, wired up with your solenoids, and throw the float switch in series with your fill solenoid/relay.

You will need a way to address chlorine/chloramine. A lot of people use RO. If you're water only has chlorine in it, you can use granulated activated carbon inline filters. GAC filters will even remove *some* chloramine, but definitely not all. Otherwise you'll have to figure something else out.

You may be interested in this thread over on TPT:

http://www.plantedtank.net/forums/equipment/34969-my-automatic-water-changer-setup.html
 
Ok, that makes sense except for the relay logic circuit part, is that just a timer or something? Where might one obtain these parts?
 
Ok, that makes sense except for the relay logic circuit part, is that just a timer or something? Where might one obtain these parts?

A relay logic circuit is nothing more than an "if, then circuits" written in electrical wiring, in other words, "if" the start button is pushed, "then" the water is drained until "if" it gets to the low level float "then" shuts off. "If" the water is at the low level, "then" it opens the valve to fill it back up. "If" it fills back up "then" it shuts the fill valve.

With this system, you will need to add the dechlorinator manually each time you push the water change button.

I can provide a relay circuiting diagram, and parts sourcing if you need it. PM me.
 
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