Pond Boss Forums INTRO Questions & Observations Alum and Lime to clear water

You did the test incorrectly. You are supposed to dissolve 1 Tbl spoon full of alum in a jug. Mix throughly to make a slurry, THEN put diff. amounts of the slurry into new jugs of pond water.
What you did was apply roughly 1 part per 250 of alum by volume. The way I just mentioned is roughly 1 part per 250X250, or 1 part per 62,500.
I'm sure you are near to clearing the pond. With your low ph, I would put 20# more alum and 15 to 20 # quicklime. As I said in the beginning, adding alum is either an all or nothing proposition. As we have also stated earlier, ag lime is ground rock, thus wont do you any good in the short term. Very slow to dissolve. It wont do anything for the ph swing. It buffers the water to prevent quick and drastic ph changes that occur throughout the day. But takes a few weeks to start doing this.