The setup with a feed zone for growing crystals from aqueous solutions at a constant temperature difference was implemented in this work. It combines feed and growth zones in one block. The capabilities of the setup developed were demonstrated by growing K2Ni(SO4)(2)center dot 6H(2)O (KNSH)/K2Co(SO4)center dot 6H(2)O (KCSH) bicrystals and KCSH/KNSH/KCSH tricrystals. The influence of initial supercooling and substrate orientation on the inclusions formation at the KCSH/KNSH heteroboundary was studied by X-ray topography. The KCSH/KNSH bicrystal grown at 1 degrees C initial supercooling on the (1 1 0) KNSH substrate shows 77% transmission that is close to the transmission of mono-component Tutton salts and allows using bicrystals as optical filters of the solar-blind range.