Be careful of flimsy plastic bottles if you use the venturi! It provides
just enough suction (IME!) to partially collapse a soda bottle while the
liquid is warm.

The method I use now is to insert a hose into a hole drilled at the base of
the riser tube. The bubble rises through the tube to the powerhead and is
smashed. The shroud directs the smashed bubble back down into the water.
Very little of the bubble makes it to the surface.

It's not as effective as injecting it into the canister, but it's pretty
good.

My problem with tees, and gang valves, and check valves, and what-have-you,
is leakage. Wherever possible I use a single tube direct from the bottle to
the tank - you may need to develop a little confidence in not blowing things
up before you're ready to try that, though.

kush

"You can't have everything - where would you put it?"

WD wrote in message
news:yQNba.57197$3D1.2148@sccrnsc01...

"kush" wrote in message
...
I use three 2-liter bottles on my 75 gallon with 2.5 watts per gallon,
one
on a powerhead and two into the canister filter. I'm usually behind on
my
maintenance so, frankly, probably only two of them are fresh on any
given
day. It does the job.

I suppose it's worth trying. Would a few 'tees' on the venturi on a
powerhead provide adequete dispersion? No canister, I use a wet/dry sump
for
filtration.