Pond Boss
Posted By: MsH Alum - strike one. Alum - strike two. Now what? - 07/31/18 02:16 AM
I've done two alum & lime treatments on my pond, and... nothing. I'm guessing I need to significantly up the ante on dosage but I'm afraid I'll use too much. Is it possible to overdose alum & lime?

Did the jar test. Started with 1/2 TBS in a one quart jar. Water was gin clear almost immediately. Kept backing down until it was down to a pretty tiny 1/16 TBS in the quart jar (i.e., 1/4 tablespoon alum per gallon). Still cleared in less than a minute.

Pond is quite small - only .15 acre, but averages 6 feet deep. So, about 0.9 acre feet. Ph tested at 7.5 to 8 before and after both applications.

First application was about 7 lbs alum and 3.5 lbs hydrated lime. Zero effect.
Second application followed 1.5 days later: 10 lbs alum & 5 lbs lime.
Noticed a few areas of flocking on surface shortly after... then nothing.
Alum slurry was well mixed and sprayed over entire pond surface, followed by lime slurry, which was thrown out using a dip can over entire surface. Aeration was kept off.

I have 33 lbs of alum left, and plenty of lime. Should I use all 33 lbs? Do I need more than 33 lbs? What happens if you use too much?

This pond was dug 2 years ago in heavy clay and has never cleared. It does not get any runoff water at all. It is well stocked with fish (hybrid bream, 6-8 bass, 2 catfish, 2 triploid carp). The jar test proved what the problem is, but now I want to fix it (without killing my fish). Help!
Might want to PM Rainman. He is the pro on muddy water
I also am having an issue with muddy water from clay. I'm following this to learn along with ya...
/c
MsH, KapHn8d....I have never gotten good results with less than a 200 pound dose of alum slurry, followed by 100 pounds of Hydrated lime per acre foot of water volume.

As for an "overdose" of Alum, that is an extreme amount...probably in the range of 5000 pounds per acre foot.

If there is any "trick" to applying the hydrated lime and alum, it is to apply the alum, as a slurry, proportionately to water depth followed by Hydrated lime, proportionately, but also in "strips" so the Hydrated lime can spread slowly and avoid any risk of pH shock....Alum does not dissolve into the water, Hydrated lime does...Alum lowers pH relatively slowly while Hydrated lime raises pH to lethal levels very quickly.

MsH...Alum applications are not cumulative...If you need 200# to clear the pond, but instead apply 4 app of 50# each, you will still need 200# applied to gain clearing.
Good Brian...Great to see you posting!!! I had been wondering how you have been and was going to call you!
Call me anytime Rex. I got nothing going on!
Thank you for the reply! Sounds like another trip to the co-op is in order. Hopefully they have more alum in stock.

Will post results after next effort!
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