Water Auto Top-Off

Have you ever wanted to save the time and trouble of constantly adding make-up water but you don't have a purified water line plumbed to your sump?

Then the GLUG JUG is for you.

What is a Glug Jug

It's a container of water that fills the tank whenever needed, automatically. The container can be any size that will fit in the available space. The container needs to have stiff walls and be completely water/air-tight. The 3 gallon rectangular blue jug available at the grocery store on the purified water aisle works really good for this purpose.

It's as simple as running a tube (as short a distance as possible, preferably only a few vertical inches) from the spout to the tank, or if you have a sump the tube needs to run to the sump. The end of the tube needs to be positioned at the desired water level.

With the jug filled partially with water set it above the tank/sump somewhere and try it. (I suggest trying it in the sink first. ) Turn on the spout valve and the water will run out of the jug until the tank water level rises above the end of the spout. As the jug releases water, air will be sucked in, usually in large glugging bubbles, hence the term GLUG JUG. This action will stop when it cannot suck any more air. It will go again when the tank water evaporates and the water level again drops below the end of the tube.

If it doesn't work this way for you, you may need to drill a hole at the top of the jug and add a siliconed in airline leading to the water level. This will make a quieter reverse whistle sound rather than a glugging sound!

The 3 gallon jug usually lasted 4 days on my 75 gallon tank with RD Refugium. I could overfill the refugium all the way to the overflow mark and it would last a week before needing water again. The same could be done with a tank without refugium/sump.

Don't worry, your sump will still tell you when it's low on water, by the usual pump "sucking air" sound. And in my experience the gradual change in salinity, from totally filled (~1.020) to sucking air (~1.024), causes absolutely no problems.

Feel free to call me for help.

Edited by Mark Peterson

Yes that's exactly the way it works.

I should mention that I didn't trust the seal on the the rectangular container so I bought a large rubber seal at Home Depot in the bathroom plumbing section.

Suzy has (or had) a glug jug.  Her's was the first one that I had ever seen.  Gravity & pressure operating devices are always cool.