Re: Eheim runs dry --

["S. Hieber" <shieber at yahoo_com>]

Cavan, adding CO2 through his E2222 is having problems with
the filter running dry -- this started after a cleaning.
I don't know but want to offer a couple of things:

They are designed to burp out small amounts to prevent
accumulation but you are adding to any small amounts with
CO2, which gives it a bigger job to do, but one that it
should be able to do.

Eheim canisters operate under slight vacuum.  The pump
sucks water out of the canister rather than pushing water
into and through it.  This helps prevent small leaks but if
any small air leaks exist, the filter can take in too much
air from a number of places.  

The newer Eheims, like the 2222, have some improvements to
reduce the likelihood of air leaks, but they aren't
foolproof.  

[Also, while we're on th subject and although this doesn't
appear to apply to your situation, if the media becomes
loaded, the vacuum increases and the vapor pressure
changes.  Then it's harder for CO2 or any gas to remain in
the water without bubbling out.  Unclean Eheims tend to get
bubbles inside.  The reduced flow from the loaded media
make it harder for the pump to drive out any bubbles that
are collecting.  Add up the vapor pressure, air leaks,
adding CO2 gas -- you can get a run-dry situation.]

Try opening and reseating the motor unit onto the canister
but first, push or otherwise manipulate the gasket so that
it is completely seated against it's bed on the motor
housing and then apply some clean vaseline around the
gasket before placing the motor housing on the canister.
{Also, buy a new gasket and keep it on hand as a spare --
the pump is useless without a good gasket.]

Also, doesn't the 2222 has a small slot/water channel on
the side of the impeller chamber ( a small securing piece
piece of triangular plastic goes in there) -- be sure to
brush out the impeller chamber using the 1/4" diameter
brush to get into any small channels.

Lastly, make sure there is no significant bubble in the
intake tube anywhere.  I have had these unexpectedly occur
-- sometimes after a water change and sometimes not.  But
they badly restrict the inflow and then the pump can't pull
enough enough water to get rid of bubbles in the canister.

Hope that helps.
Scott H.

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