Path: utzoo!hoptoad!ptsfa!ames!aurora!agate!ucbvax!sdcsvax!sdcc6!calmasd!jnp
From: jnp@calmasd.GE.COM (John Pantone)
Newsgroups: alt.aquaria
Subject: Re: Tank Size
Message-ID: <2634@calmasd.GE.COM>
Date: 23 Jan 88 00:34:08 GMT
References: <5927@sol.ARPA> <2196@gryphon.CTS.COM>
Organization: G.E.- Calma R&D, San Diego, CA
Lines: 27

> The question was asked "are hex tanks any good".

Many folk have, correctly, pointed out the relationship between surface area
and number of fish - but there is more to the story.

What we're really after here is oxygen/carbon dioxide exchange (O2 into the
water - CO2 out) - this normally occurs at the surface of the water/tank.
If nothing else is done a hex tank is really not "very big" and can't handle
too many fish.  There is a solution, though, wich we used in our hex tank
several years ago:

put a glass or plastic tube 1/2 to 1 inch in diameter into the tank - and
support the bottom in such a way that water can enter the tube (we propped
it on a piece of lava-rock).  Get one of those air-bubble stones and a
plastic tube (can run down the large tube) and connect to an air pump.  This
will do 2 things - 1 it will "lift" water up the tube, and cause increased
gas exchange at the surface - 2 it will aerate the water "artificially" with
all those bubbles - increasing the gas exchange again.

I tried to calculate the efficiency of this, and ran across some figures
about moving water in streams, etc. which indicates that it could as much as
double the effective surface area of a tank.

-- 
These opinions are solely mine and in no way reflect those of my employer.  
John M. Pantone @ GE/Calma R&D, 9805 Scranton Rd., San Diego, CA 92121
...{ucbvax|decvax}!sdcsvax!calmasd!jnp   jnp@calmasd.GE.COM   GEnie: J.PANTONE