Cool non electric diy auto top off I found

[Nano sapiens]

It doesn't form a vacuum, and then stop dripping? Do you have the spout submerged, or above the water line? Thanks! I am looking for dosing idea like this for tanks with hang on filtration. Presently am using siphon drip from liter bottles.

The spout should just barely submerged at wherever you want/have your water line. As the tank water evaporates, air will enter the tube and bottle, thus displacing water until the tube end is submerged again. Cycle goes on and on until the bottle is empty.

This what it looks like in cross section (the pink dyed water was to prove that diffusion into the bottle does not take place):

Simple, foolproof...and best of all no float switches to get stuck or motors/timers to fail

 

[DFW]

The spout should just barely submerged at wherever you want/have your water line. As the tank water evaporates, air will enter the tube and bottle, thus displacing water until the tube end is submerged again. Cycle goes on and on until the bottle is empty.

This what it looks like in cross section (the pink dyed water was to prove that diffusion into the bottle does not take place):



Simple, foolproof...and best of all no float switches to get stuck or motors/timers to fail

Thanks for the reply!

I guess that this won't work for me because I want to mount it on top of the hang on filter, and the water level stays the same in the filter all of the time. I am thinking about using an applicator bottle. They drip one drop at a time, so will be good for dosing a small tank directly into the hob filter. I figure to drill hole in filter cover to rest the bottle, and cut a hole in the bottom of bottle (top after it is turned upside down, and placed on filter) for filling using a funnel. Or maybe I can devise a holder similar to a cup holder to hang inside tank. What do you think?

 

[Skydvr]

An irrigation drip emitter may help reduce the drip rate to something more useable if you do a continuous drip method. I use it with my pressurized ATO to slow the rate at which the top off water is added.. You can pick them up at hydroponics or gardening stores for ten to fifteen cents each. 3/16 airline slips over one end. They typically come in .5, 1, 2, 3, and 5 gallon per hour, but those ratings are for pressurised systems, so with a gravity fed system (or air pump driven in my case), it drips slower.

 

[DFW]

An irrigation drip emitter may help reduce the drip rate to something more useable if you do a continuous drip method. I use it with my pressurized ATO to slow the rate at which the top off water is added.. You can pick them up at hydroponics or gardening stores for ten to fifteen cents each. 3/16 airline slips over one end. They typically come in .5, 1, 2, 3, and 5 gallon per hour, but those ratings are for pressurised systems, so with a gravity fed system (or air pump driven in my case), it drips slower.

That's an idea! The bottle does drip too fast really. And I have those emitters laying around anyway. Thanks!