Bottom posted.
LM wrote:
Hi everybody,

Thanks for all the message. After more research I decided that for a
QT tank, using a quieter air pump may be a better choice (with
corner/sponge filter)... (flow rate, oxygen circulation, cleaning all
considered)

so.. decided to get the Rena air pump instead of getting the internal
filter.

thanks!
linda

Congratulations on making a good choice! The rena's are the best all around
pumps out there. I only brag about my tetra luft pumps because of their
sheer power, and the dynamaster (I don't have one of those) piston pump is
good but NOISY. The luft pumps are somewhat noisy. And the luft piston pumps
are unproven as of yet (the old dynamaster might actually provide more air
pressure than the luft piston pumps) and the rena's are comparable in power
with the slight possibly in my opinion that the rena's might actually be a
little more powerful than all others except for the air volume provided
(i.e. it provides as much or more pressure but not volume as the other top
pumps). I don't recommend the airmasters unless you definitely want
something you can repair and you don't have a deep tank or air walls (I
don't think my airmaster never worked at the bottom of my 55 gallon so I
used it to power a bubble wall or two in my 15 usa gallon tank and it could
not do that either so I ultimately use it to power 2 airstones in my 15 usa
gallon tank), BUT the airmasters are cheap! Good luck and later linda!