So instead of nerding out on you and making you wade through an article with chemistry, I will just give it to you straight and then fill in the details… liming is nearly the same… exactly the same as giving your pond/lake a Tums antacid tablet. It has other advantages, but let’s start there. Ever had that meal that triggers indigestion as a result of overproduction of acid in your stomach? The first thing recommended is an antacid tablet – Tums, Rolaids, etc. If you look on the label, these are calcium carbonate. It neutralizes acid, and you get relief. Many ponds lean towards an acidic condition from the watershed that feeds rain runoff to the pond or from the well-water used to fill it. Acidic conditions limit fish production/growth and health, as well as limiting the cycling of nutrients. Adding lime in the form of calcium carbonate counteracts these limitations.
Some other straight talk on liming, but more specific…
Agricultural lime is mostly in the form of dolomitic lime, which contains calcium and magnesium carbonate. The calcium and magnesium increase hardness and the carbonates increase alkalinity and buffer against pH changes.
Ponds are active with biology including algae, that through photosynthesis, respiration, and bacterial consumption of organic material, change pH throughout the 24 hour day. These pH swings are stressful for fish. Alkalinity in the pond at 50 ppm or more can help to reduce fish stress and increase the general productivity of the pond or lake by helping to cycle natural nutrients in the water and mud. This helps to keep your pond in a healthy pH range between 7 and 9 with slower and less dramatic pH swings.
What about the hardness components of calcium and magnesium? Well they have their benefits for the ecology as well. These minerals start by increasing the survivability of hatching fish eggs. Then they help to provide minerals for the frame of a growing fish, and also to provide shell materials for crustaceans of all sizes, a valuable food source for your fish. These minerals also help with electrolyte balance in the fish blood stream, reducing stress.
We recommend liming proactively on new ponds/lakes, or at least getting your water tested. The benefits are many and if done in the right volume, the treatment should last for several years.
