Thanks for your suggestions. Unfortunately the mixing box is glued shut, although I should be able to tape a peice of gel over the inlet window. That might just solve the problem. BTW, adding cyan does lengthen the exposures, plus it's a very pretty color.
I'm wondering why I seem to be the only one with this problem. My negatives are not thin by any means, they are amply exposed and well developed. I have searched the web looking for advice and found that most people were troubled by their V35 being too dim not too bright. I guess I'm just lucky.