In a small growout pond (GT) really watch the alkalinity when using alum. You want the alkalinity as high as possible (within limits) prior to starting. Small waters can change quickly causing stress. Avoid quick changes as they cause death.

Have hydrated lime on hand and use it as directed during the process. However that is not what I am talking about above. Start ahead of the change curve by having good alkalinity before the fact by adding ag lime well in advance if needed to raise alkalinity. The best results would be an alkalinity high enough before hand that the alum does not cause a change. Also ag lime will sometimes clear turbidity or at least lessen the amount of alum required as it is also a flocculent.

I have pvc depth gauges marked with lines with a big black line for full pool.