Sounds like this could be a good discussion, albeit splitting hairs. I
think you are taking a little bit of liberty with Spotte's work in saying
that there is more water flow without airstones. The more bubbles, and the
finer the bubbles, in the airlift displaces more water, causing a negative
pressure in the lift. This, in turn, causes the water below to "fill the
void". According to Captive Seawater Fishes, the maximum flow rate can be
achieved with a "bubbly slug" flow of water in an airlift. This however is
usually only effective in larger diameter and larger length airlifts than
what we normally achieve in our home aquariums. For our purposes, I have
always known an airstone to create the most uniform and rapid flow of water.
A tips for increasing flow are to make the airlife as tall as possible, put
the airstone as far down as possible in the lift (as long as the pump can
take the verticle pressure) and finally flare out the bottom of the airlift.
This actually creates less friction for the water to enter the lift. It is
also interesting to note that a properly designed airlift "at maximum
pumping efficincy equals or exceeds that of centrifugal pumps". Doesn't
sound possible, but that is the beauty of air.
With all this said, I rarely use airstones simply due to the b.s. factor.
Although I am primarily concerned with maximum flow rate, I will sacrifice
some of that flow for not having to change the dang airstones every time I
pass the tank!
Could you send me that .pdf of Spotte's work? I would like to add it to my
For all those who are still reading this longwinded microanalysis of
airbubbles, Spotte has great works on aquarium science. One could create a
500 level curriculum in aquarium sciences just on his work alone. All of
them are fantastic references.
Also, get a life if you like this stuff ;)
Cleveland Metroparks Zoo
216.661.6500 ext 4485
From: owner-nanfa_at_aquaria.net On Behalf
Of Shane Graber
Sent: Wednesday, July 09, 2003 9:17 AM
Subject: RE: NANFA-- heh -- Now Improved with Reason (tm)!
Looks seriously cool Todd! :)
Where did you find the black stripes, fantail, and northern studfish around
here? I've wanted to collect a couple blackstripes and fantails since I've
seen pics of them. The northern studfish is one I haven't seen in our
seining trips and if they're native to Ohio I'd love to get a couple. :)
The one thing I notice is that your darters seem to have much better
coloration than mine do for some reason. What are you feeding yours? I'm
feeding all of mine Sally's Frozen Mysis, which seems to have a pretty good
nutritional profile. One other thing that comes to mind is that mine may
not be as colorful as they're trying to blend into the tank bottom and I
used a light colored pea-gravel overlay for my soil substrate and you've
used a much darker gravel in your tanks. Can and do darters and other fish
change color based on their environment?
In regards to the shrimpery: Here's how I employed airlifts on my ghetto
coral prop tub:
I found that you really don't need the extensions that run along the bottom
of the tank like you've got. It tends to increase frictional head loss a
little which will end up dropping your flow thru your airlifts. Also, you
may want to try removing the airstones and seeing how much that increases
your flow as larger bubbles will tend to "drag" more water with them as they
float to the surface. If you'd like, I've got a .pdf of Spotte 1979 that
deals strictly with designing airlifts for use in aquaria. Seriously good
read and I'm guessing that Tropicorium probably read the exact same chapter
when they setup their airlifts on their coral vats.
Also, I thought I'd throw out these articles in case you haven't seen them
> Also threw in some shots of my latest project after the
> holocaust... Gonna try my hand at raising amphipods
> (gammarids) and the like
> in my tank stands for food source. Wanted to make this as
> electricity free
> as possible. Man you can move a lot of water with air! If
> it doesn't work
> out (not efficient enough), I'll just add some salt and rear
> brine shrimp in
> it. No love lost... Had everything I used already, so I
> didn't have to go
> buy anything...
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