Where can I get a .22u and .45u sterile filter to filter my sledge test. i looked on gpz.usa and they only have .45 and .20 for water based injectables. I will be filtering about 150mls of sledge test and 1 test cyp. So I figure I will need 3 .45u filters and 3 .22 u filters. Or should I get 4 just to be safe if one breaks. I will be using a 60ml syringe or should I go smaller? Do I need to change the filter each time I change the syringe if I decide to use a smaller syringe (say a 10ml, do I need 5 fitlers so I can put a new fiter on each time I refil the syringe) and can I "stack" filters like syringe, .45 filter, then .22 filter then needle? All luer locked together?