are you mixing 1 gallon at a time? what is the ph of your water without the molasses? my water is ph8 if i put in 1 tbs bsm its now 6.8. if that helps any just make an educated guess, remember the lower the ph the more ph down it takes to lower it. ie half a tsp will lower my 8 to 7 but add another half and it only goes to 6.5 not the 6 you would think.