airstone question

[fishycanuck]

Those of you on the 911 forum have seen the problems I've had with the discus tank. I bought an air pump and airstone but found the stone was cracked, so for a few days just had the pump running as a bubbler. I attached a new airstone a few days ago, but air is only coming out of a small part near where it attaches to the tubing. Isn't it supposed to come out of the whole thing? Could the stone be too big for the pump?

[Brent Shaver]

Check your line for a crip or blockage.  You are right it should come out of most if not all the stone in the beginning.  Mine has been running for well over a year and still over 3/4 of the stone is free to release air.

It could be your pump output as well.

[sas]

Further to what Brent mentioned, check the amount of air your
pump is producing, may not be enough, or you ended up with a dud
for a stone.
I'd also check the spout at the pump, I've had those break over time,
they seem to get brittle.
That's all I can think of at the moment.

[new2salt]

+1 for Brent and sas
The only other thing I can think of is - if its an old air pump - check the pump diaphragm.
It could be split, cracked or unseated and lowering the air volume output.

Good luck

[fishycanuck]

The pump, stone and all bits are brand new. Air bubbles out freely from the tube when not connected to the stone.
I repositioned the stone and now bubbles come out of about 10% of it, closest to the tubing.
Guess I should call the store!

[Saltcreep]

I think Sas and the others may have it when they talk about pump volume. I've had many airstones over the years and many of those performed just as you describe. If the volume of air you pump into the airstone can escape close to the inlet, then it will; no need to "pressurize" the rest of the stone. It takes a certain amount of volume to fill the void in the stone before it can build up enough pressure to escape and create bubbles. My bet is if you tried a higher volume pump or hooked a couple up in tandem, you might get the effect you're looking for. When they've been in use for a while, algae or slime buildup can really restrict the airflow too.