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RE: Circulating range system

Date: Tue, 4 Dec 2001 22:39:43 EST
From: Bob Olesen

> I have a book written back in 1969 by
> Feroze N. Ghadially, MD, called, Advanced Aquarist Guide...

If memory serves me correctly, this is a small, hard-bound white book, about
5"x8" and maybe 3/4" thick, with the author's photo on the back (an Indian
or Pakistani doctor). Inside, he speaks of just about every "Do-It-Yourself"
aspect of the hobby imaginable, and does one of the first really "bang-up"
jobs of describing the different aspects of water chemistry that you could
expect from a serious hobbyist.

This book was one of my earliest TRUE inspirations in the aquarium field,
and if I have correctly described it I would sorely appreciate the
publishing info so that I might be able to track down a copy.

> ...wherein the author describes a "circulating range" system
> that connects two levels of tanks together by siphons and
> an airlift. The water is maintained at a certain height by
> an "automatic leveling siphon"...

Also known as a "self- leveling siphon", and it actually works. I've formed
them from various sizes of plastic and PVC tubing by filling them with sand
and heating the bends with an electric paint stripper (hot air type). The
sand keeps the bend from collapsing while the material is pliant.

It's crucial to have the breather hole up at the very crest of the second
"loop" if the flow is to be broken at the proper time. Too far to either
side and the siphon leaks either air or water, depending on the direction in
which you move. It also needs to be a fairly large hole - at least 1/8-3/16
inch - else surface tension will form a "skin" over the hole that the
ambient air might not be able to break through and there's nothing to
"break" the flow. The height of the second loop will then determine the
final level of the affected tank.

There is a GIF file I keep on-line to illustrate any points I usually make
http://www.mindspring.com/~nestor10/trials/slsiphon.gif . I use this URL
mainly to accompany UseNet postings, where most of the groups I follow are

Another consideration is the inside diameter of the tubing. It should be
much larger than the stream you expect to maintain through the tubing.
Otherwise, surface tension may again close off the air hole and the device
becomes a regular siphon. You must leave enough room inside the tubing for
the water to flow or "cascade" over the lip without filling the chamber
right there at the top of the loop. If you're expecting a large or swift
flow, then a tube larger than 1" can be moderately flattened to conserve
some space and keep the double looped siphon from becoming a huge, unwieldy
device. This is perhaps the biggest reason for using an airlift as the
return - a full- blown pump might overtake the siphon.

I still use these siphons today. They are extremely handy for things like
water changes in fry and rearing tanks. There I can introduce a slow flow of
incoming fresh water for a while without worrying about watching the tank or
sudden, drastic changes in temperature, etc..

> I believe one tank in his system is a Daphnia only tank
> which, it is claimed, allows for much greater fish loads
> with little to fear in the way of pollution.

The concept is based on recreating as much of the natural setting as
possible in order to handle the environment of the tank in a "natural"
manner. Fish leave a lot in the water, and between their waste and excess
food, etc., things like dissolved organic carbons (DOCs) build up. Creatures
like Daphnia, protozoa, rotifers and such are then capable of utilizing the
DOCs as food sources, but the fish also like to eat the "bugs". Separate
tanks allow for separation of the populations. Think of it as a freshwater
"protein skimmer", where many of the pollutants are removed prior to
reaching the main filtration system.

The only change I would make currently would be the addition of a third tank
set up "hydroponically", to allow for vegetative filtration prior to the
water's eventual return.

> Does anyone know where I can find some additional and hopefully
> more current and detailed information or ideas for connecting
> and maintaining a small number of tanks in a series?

One of the more advanced hobbyists from Russia has often asked me to go into
detail about such a system, and until lately I haven't any time to myself
(hence my prolonged absence). I guess now would be a good time, so feel free
to ask me specifics if you'd like. I can then forward copies to Sergey and
do him some good as well...


David A. Youngker
nestor10 at mindspring_com