MgNH(4)PO(4)center dot 6H(2)O (struvite) was crystd. from dil. aq. solns. of PO(4)(3-) (1% by mass), Mg(2+) and NH(4)(+) ions (mole ratio 1:1:1) in a continuous draft-tube mixed-suspension mixed-product removal reactor in presence of MeCH(OH)COOH (0.03 or 0.06% by mass) at varying pH (8.5-10) and residence time (900-3600 s). The addn. of lactic acid resulted in an improvement of struvite crystal quality. The mean crystal size was 24-74 mu m. The max. crystal size was achieved at pH 8.5-9.0 and residence time 3600 s at the lowest nucleation rate 5.6.10(7) 1/(s.m(3)) and linear crystal-phase growth rate 6.11.10(-9)-2.23.10(-8) m/s.