Check valves

To: Aquatic plants list <aquatic-plants at actwin_com>
Subject: Check valves
From: Cynthia Powers <cyn at metronet_com>
Date: Tue, 17 Dec 1996 18:23:17 -0600 (CST)

--------Forwarded Message -------------
From: "/PN=Steven.S.AMOR/OU=ENG4/O=SHELL AUSTRALIA/"@shell.otc.au
Date: 17 Dec 96 18:17:02 +1100
Subject: Check (non-return) valves 
To: Aquatic-Plants at actwin_com (Receipt Notification Requested)

Hi,

I've lost the little spring and plate inside the non-return valve of my Dupla
CO2 system.  Short of buying a new one, which is very expensive no doubt, does
anyone use a cheaper valve?

I know that there used to be cheap ones around for connecting to an air hose
from a pump to stop the water syphoning out of the tank if the air pump broke. 

Do you need a good quality valve that doesn't leak at all?  What sort of vacuum
is formed when a CO2 bottle empties? What would tank water do to the inside of
a bottle?

Thanks,

Steve Amor
Steven.S.Amor at Shell_otc.au