| | Re: Automatic water change system design DIY
Just a quick update on the system (over a year later). There have been no leaks from the saddle valves or plastic lines. Though if you make this system you definitely need to keep the tubes away from anything that is too hot to touch, especially furnace exhaust vents (hot water pipes seem ok for the most part as long as you can touch them with your hand). I had a small leak from one solenoid that seems to have been defective though which didn't cause much damage since it was only a few drops.
The main problem I've had with the system is that it flushes nutrients out of the tank very quickly. I also found that if you run the water too much (constantly 24/7) fish develop pop-eye from gasses dissolved in the water (similar to the bends divers get).
I had to dial back the time that I allowed the system to run each day. I now run the water change system for 15 minutes a day which is the lowest increment on my timer. I think running it even less then this or 2-3 times a week for a short time would be even better.
Since I posted this I added an RO unit and water storage tank to the existing system for my discus 180g tank. I suppose with a few plastic fittings I could mix RO water in with the other tanks I have if I wanted. I might post pictures of the RO system.
When I find time I'll wire up some peristaltic dosing pumps to the tanks to automatically take care of the fertilizers.