Digital BW, The Print

Last year I purchased two different Continuous Ink Systems for my two  
Epson 2200.  Both came from China.

The designs were slightly different, but both seemed similar to what  
MIS and others sell.

Both worked nicely for two or three months, and then in February or  
March they *both* started giving me trouble. In particular, neither  
one would keep the supply tubes from "running backwards" and sucking  
in a great deal of air.  Originally the supply tubes had remained full  
once I got everything set up and primed.

I finally just "retired" both systems and went back to my MIS  
refillable cartridges.

...Any idea what was happening?  By that time of year the humidity in  
my home would be pretty low, and I think that both started failing  
after sitting unused for a couple weeks while I marked exams.

Any suggestions?  The seals on the bottom are that clear latex-y sort  
of stuff.

BTW, the only cartridge that continued to work reliably was a  
*replacement* cartridge that I had made from an MIS refillable.

(How did I re-engineer the refillable cartridge?  I covered the tiny  
vent hole on the top with putty-like window sealant, resized the  
filler hole so that the CIS tube and gasket would fit, replaced the  
chip with an auto-reset one, put the supply-tube/gasket assembly in  
place and primed/filled the cartridge from the supply tube.)

Myron