Struvite was crystd. from aq. solns. of NH4H3PO4 (concn. of PO43- ions 0.20 or 1.0% by mass) and MgCl2 at 298 K, pH 9, PO43-:Mg2+:NH4+ ratio 1:1.2:1 and residence time 900 s in presence of Al3+, Ca2+, Cu2+, Fe2+, Fe3+, K+, Zn2+, NO3- and SO42- ions to study their effect on the product quality. Draft tube process with suspension mixed product removal was used in the study. Properly shaped struvite crystals (mean size 28.8-51.8 mu m) were produced but the ionic impurities influenced homogeneity of the crystals as well as their structure and habit significantly. In the presence of Al3+, Ca2+, Fe2+ and Fe3+ ions, their hydroxides and phosphates were also formed and remained in the product.