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DIY auto top off


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Well, I wish I had pictures - but no digital camera at the moment. I'll try to borrow one later and get ya some.


Finished my air driven auto top off monday night, got it running tuesday. Been working fine ever since. Just need to build a permanent snail guard for the float switch, then we're done.


It's actually really simple, started with a penn plax battery powered air pump, and an electric float switch (9.99cdn from aquaria.ca). Roughly 22$ in parts there. Then I drilled a 5/64" hole in the top of the air pump case, fed the wires through the hole - siliconed them to avoid any SW creeping into the pump. Pulled out the soldering gun, removed the black wire leading from the on/off switch to the motor, and then soldered the leads from the float switch to them. (This way the two are in series, and you can shut off the 'top off' for water changes etc).


Made the mount for the float switch out of an old hagen HOB heater - perfect height for my tank - full I've been keeping it at the plastic trim anyway. Snail guard for the moment is built from an old fish food container with plenty of holes drilled in it - it's ugly going to replace that soon with a hunk of PVC or I might just take it off and move it to the refugium when I finally get it together.


The rest was simply a 2L pop bottle, 2 11/64" holes drilled in the cap, one for a air line connector, the second, for some 3/16" thin wall hard line from the LPS - the hardline sits just off the bottom of the pop bottle, and extend about 1" past the cap. I then siliconed the heck out of the cap making sure there were no leaks.


Once the silicone dries, it was just a matter of running some air line from the pump to the air line connector on your resevoir. And running some more air line from the hardline (airline with a bit of heat will just slide over the hardline) to the tank, in my case I feed it to the HOB filter cover - so it gets mixed a bit before hitting the tank


It's been working great for 2 days now on my 2.5. Every 90 minutes or so the air pump gurgles to life for a second or two, water levels been rock steady at the plastic trim level.


Next job will be to replace the batteries with a 3v power adapter. But I might just leave that - a friend recently moved and apparently the 2D batteries are plenty to run the pump for 4 days straight. Should last for years in the auto top-off.



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