Viking,
Was this single-strength liquid rennet? If so, it ought to have been far more than enough to set 8 liters - most recipes I use about 1/4 tsp of liquid animal rennet per 8 liters. (I just saw Sailor's post come in - using even more rennet sounds like too much to me, but he is far more experienced than I am ... ?)
It seems that people's experience with using the flocc method for pasteurized and homogenized milk differs pretty widely. For me, I have never been able to use the method successfully ... except for the one time that I tried making cheese with half raw milk + half P&H milk. The difference was unbelievable - up to that point, I could never get a clean, clear time for the flocculation, but with even half of it as raw milk, I finally understood what the flocc test was supposed to look like.
Unfortunately, where I live, raw milk is very expensive and hard to get (it is actually illegal to sell it for human consumption in my state), so I have not yet been able to afford to replicate that one wonderful experience. (And by the way, the cheese that came out of that batch was markedly better than any other I've made, before or since.)
Again, some people seem to be able to use the flocc method with the P&H milk that they have access to, so results seem to vary ...