Pond Boss Forums MANAGING AN EXISTING POND Fertilization Ag Lime differences

Ag lime is available in two different forms around here. Standard lime is a tan color like sand, $25/ton and they call it 80/90. The high dollar stuff is gray and $45/ton, but I am not sure the true difference. Is it just the fineness of the grind? I've heard the term Hi Cal lime thrown around as well.

Which is more practical or desirable in a pond remediation situation?

I have not heard of this before. What is the 80/90 about. Call and ask and then post what they say. There are different kinds of lime but not as you describe.

I am guessing the 80/90 is mesh size. 80% will pass through a 90 mesh.

You want high Cal lime or Calcium Carbonate. You can't screw up with Calcium Carbonate. 99% of the time grey lime is dolomite lime and is high Magnesium. Magnesium can be toxic if in too high of a application.

The high the mesh the finer the product the more water soluble. The more soluble the less product you need for the same effect but the less product you have to stick around as a buffer to stabilize PH after applied. Calcium Carbonate is the best buffer in the world. It will bring PH up and will bring PH down. It naturally trys to bring the PH to 7.2. I would not use any other lime on any pond if I had a PH problem.

Cheers Don.

OK this is making sense now. Sounds like we have the right stuff for the job. The lower initial solubility of the coarser grain is probably a good thing long term as well.

I'll ask the farmer neighbor what is in the "good stuff" that they use on the fields, but I'm guessing it is exactly as you stated.

Read this and see what fits your situation.

Both calcitic limestone (CaCO3)
or dolomitic limestone
[CaMg(CO3)2] are good.

Calcium carbonate hardness is a
general term that indicates the
total quantity of divalent salts present
and does not specifically identify
whether calcium, magnesium and/or some other divalent salt is
causing water hardness.

https://srac.tamu.edu/index.cfm/event/getFactSheet/whichfactsheet/112/

Calcium and magnesium are essential
in the biological processes
of fish (bone and scale formation,
blood clotting and other metabolic
reactions). Fish can absorb calcium
and magnesium directly
from the water or from food.
However, calcium is the most important
environmental, divalent
salt in fish culture water. The presence
of free (ionic), calcium in culture
water helps reduce the loss of
other salts (e.g., sodium and potassium)
from fish body fluids (i.e.,
blood). Sodium and potassium
are the most important salts in fish
blood and are critical for normal
heart, nerve and muscle function.

We have had farmers put on dolomite lime on high mag land it will not have the effect that calcite or calcium carbonate will. High mag will make the plant turn very dark green as well as your algae. To much will act and look like to much nitrogen. But very very dark green colour.

If your water has high mag now it would be very bad to add dolomite lime. Calcium carbonate is the most abundant mineral on the face of the earth and is cheep. Highest cost is trucking.

Cheers Don.