The alum needs to be mixed with enough water such that it is dissolved before it enters the pond. Which size crystal of alum do you have? The alum I bought was "standard ground" - like coarse sea salt - quite a bit bigger particle than the "fine ground". I found I needed to slow WAY down on adding alum to my mixing tank otherwise whole crystals were being blown out into the pond and sinking which gives poor results.

I'm not sure I subscribe to the all in one day or all is lost theory. My pond was much improved when done for the day, but I wasn't quite satisfied. I came back a week later and added more - adding another foot to the secchi reading. Been great all summer even after a 6" downpour. knock on wood...

edit - I remember now ; after done for the day my secchi reading was 30" or so. The next day I showed up and the wind was howling. Standing on my dock the water was gin clear down 60". But the other side of the pond was muddy with an obvious line. What happened was the clear surface water was blown to one side. I needed to treat more and did it the next weekend (had to get more alum).

edit #2 - I did this experiment: poured in the 1.1 grams of coarse alum I knew would treat 5 gallons. Did NOT stir it for 5 days. Nothing happened - still muddy water. Then stirred up and it flocced and sank within an hour.

Last edited by Redonthehead; 08/27/20 02:07 PM.
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