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Re: Water exchange system

> Date: Mon, 18 Jun 2001 20:54:33 -0700
> From: J & D Olberding <jdolb1 at home_com>
> Subject: Water exchange system
> I am seeking information/directions on DIY water exchange system for
> multiple tanks. I wish to put in a low budget, permanent, or at least, a
> "remain in place" system that is easy to use, less tedious, less time
> consuming and more water saving than individual tank exchange method like
> water Python gizmo. It need not be automatic. I don't mind turning on a
> valve or two. Just give me relief from servitude to 20+ tanks.
> If seems too off topic, contact me off list.

Sounds on-topic to me, so here goes.

Horse-trough fill valves or ice-maker valves can be used to keep a supply
vessel at the exact height you want for your tank(s). Toilet-tank valves
work, but require tougher plumbing. The top water level in all tanks served
must match, tho. Manual valving is also possible, I guess, but requires more

The problem is reliably getting water in and out of the tanks. Simple
inverted siphons can let water go from the supply reservoir into the tank,
with no problem. The tank water must never get below their entrance or exit,
and they will never lose priming.

To avoid drilling glass, the problem is to get a 100% reliable, self-priming
exit siphon. Here's the way to do that.

Buy a length of that translucent tubing sold for ice-maker installation at
Home Depot o/e. It is a stiffish polyethylene and a bit tough to work with.
If you push a stiffer piece of wire (coat-hanger or a bit heavier) through a
piece of it, you can bend a "J" shape in it. If immersed in boiling water
for a few minutes, and allowed to cool, the bend becomes permanent. Tie/tape
a thick piece of yarn to the end of the wire, before removing it, so the
yarn is drawn clear through the tubing. Cut the yarn so a bit hangs out each

Hang the "J" inverted with the short leg inside a tank. The yarn quickly
wicks the water up and over to start a drip on the outside of the tank.
[Those of us who use yarn spawning mops have all learned how quickly a tank
can be drained by leaving a strand hanging outside. :-)]

The drip can be directed into your drain pipe by having a hole drilled that
each outlet siphon hangs into. By making the short leg of the drain siphon
tube shorter than the inlet siphon "J" tube, including any protruding yarn,
you assure the inlet siphon stays full and doesn't lose prime.

The inlet siphons can be made the same way, but without yarn to obstruct
faster flow. The outside end needs to rest in a piece of PVC pipe mounted so
the water level is about 3/4 of the way up the pipe diameter. Use a
baby-ear-bulb syringe to start the siphons.

There are lots of other ways to do it, but I like the inherent reliability
of this one. The tank water can never go so low it strands fish or plants,
and the plumbing is fairly easy to hide.

That said, I never use such systems for a few simple reasons. I have too
many tanks on too many levels. I *like* to do manual water changes so I can
see what's happening in each tank. I haul shoeboxes to the sink, use a
pitcher for 2G tanks and drum bowls, and a portable siphon with bulb starter
(cheap kerosene pump from Ace hardware) for draining, and another hose with
horse-trough float valve for filling (without carpet soaking when I forget
it). I use a gravel vac and bucket for cleaning out mulm and touching up
gravel, too. The auto-change systems never seem to do that for me. :-)

Good luck with it, June.


Wright Huntley, Fremont CA, USA, 510 494-8679  huntley1 at home_com

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for the general welfare but only those specifically enumerated."
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