One filter, two tanks... possible?

[kumdoalan]

When I lived in my house in Seattle about 10 years ago I had a 2-tank/one filter system for a while.
The two tanks (A 20gal and a 40gal) sat side by side and I just got a 2" water pipe that went in a "U" shape connecting the two different aquariums. I had the filter sucking out of one and pumping it to the other.
The 2" pipe was like a water bridge between the two tanks and as water always seeks it's own level the water was always going from one tank to the next.

In real life how it worked out was that one tank was always had a slightly higher water level than the other tank, but it did work and all the water in both tanks did get to the filter.
It more or less worked as if the two tanks were just like one really big tank with just some glass set in the middle of it.

 

[FSM]

Yeah, you can do it with the water bridge thing, but the water in both tanks will mix, so you can't have two different types of fish. They all have to have to same water needs.

 

[unstopable4700]

like dr.joe stated second tank is getting raw end of the deal by getting every thing that comes from first tank. maybe if it was bio only but would be useless as mechanical

 

[kumdoalan]

like dr.joe stated second tank is getting raw end of the deal

Yes, the 2nd tank would be more-or-less a pre-filter settling tank for the first tank.

There must be other ways to run this design of one filter for many tanks because dont many Local Fish Stores have some way to run all their display tanks off of a common filter?
...

 

[koop171]

would a water bridge not need a vacuum to do this properly and if so what happens if the vacuum is broken .... water on the floor and an empty tank

 

[kumdoalan]

would a water bridge not need a vacuum to do this properly and if so what happens if the vacuum is broken .... water on the floor and an empty tank

The way I had it working the pump/filter sent water into the first tank and sucked water out of the 2nd tank.
This means that there was always a little difference between the levels of the two tanks and thats why the water would flow from the higher to the lower.
But the moment the power went off or there was a interuption in the water flow it would mean that water would stop filling the first tank, or stop going to the filter, so this more of less kept anything bad from happening.

So it deppends on a person's design as to the danger you run of a empty tank.