I guess it all depends on the quality of the ink you already have in there as to whether
you’ll have problems mixing them together or not. I wouldn’t think there would be any
problem but you’ll never know for sure until you try it. Some of the CIS systems that
are sold on ebay do not come with very high quality ink unfortunately. I only use ink
from printonadime in my refillable carts and will be using the same ink with my soon to
be installed CIS system from printonadime also.