Digital BW, The Print

I am having a clogging problem on an Epson Stylus Color 1160.  I ran a nozzle check  and alignment with Epson ink, used flushing cartridges
and then installed Piezography BW ink.  Now I cannot get a good nozzle check pattern.  I ran a cleaning cycle four times, let it sit overnight
and ran four more cleaning cycles but it still hasn't cleared up.  I've check to make sure that the 'vent' is open but not 'too open' on the
cartridge and that the vent is not blocked by the foam pad.  Any ideas out there of why the heads are staying clogged when they worked
perfectly before I installed the new inks?
Thanks for your help,
Anna Doehring