[ccp4bb] How to slow down crystallization? Need hep!

[lei feng]

Hello everyone, I need your suggestion for slowing down crystallization for my 
proteinmy protein got hit in PEG/ION #5 ( 0.2 M MgCl2, 20% PEG 3350, pH 5.9), 
but it crystallize too fast. In 1 hr I can see tons of tiny needles. Can anyone 
give me some suggestion on how to slow down the process? I used lower conc. of 
potein, lower conc. of PEG ( 10%), it helped a little bit, giving me small rod 
crystal. but no improvement after that. Thank you very much for your 
suggestions