thanks for the reply

see lots of floc as the alum is going in. It clears up after a bit, but there's no doubt where the alum 'trail' is as we were putting it in.

agree should have done the math before-hand. I was following the rules of thumb posted on this site and the Texas A&M website that indicated 100 - 125 lbs/acre foot of water. I can say that I can clear a jar of the water overnight with 3 - 5 crystals of alum. realize that's not worth diddly though since you don't know the weight of the crystals or the volume of water.

we added another 50 lbs about an hour ago. Guess we are now in the 'wait and see' phase. pH still looks to be in the ok range. it's about 0.7-0.8 lower than when we started.