That sounds right for ag lime on farm ground. We always figured months before we got much good and a year at least to see full effects.
Generally ag lime has a wide range of particle size. It goes through a grinder then sieves to sort anything out that is above a certain particle sizes. The ag lime remaining ranges from the finest particles up to the size of the sieve size. The very finest particles should do some immediate good with the larger particle size taking longer to get the good out of it.
I'm not sure how it works with pond water, but with ag land the natural progression is for ground to get more acidic over time (lower pH) for numerous reasons such as nitrogen application, etc. We always figured a land lime application was good for 6-8 years before the pH got to a point where it was economically needed again. The finest particles of the lime made the nearby correction and as the particle size increased it took care of longer term needs.
If that holds true for ponds then I would expect a product that was very active in the short term would likely need additional "shots" of it as time goes by, whereas ag lime with more capacity to buffer long term pH changes might not need to be done for years. This kind of makes sense if the liquid product suggests adding some each year.
Ag lime is nothing more than ground up rock. Limestone. The liquid stuff is something likely a lot more refined.
Last edited by snrub; 05/03/17 04:12 PM.
