Pond Boss Forums Thread Like Summary - First time lime

We built the 2-acre pond in January of 2024

Stocked bluegill and fatheads in February, with the first gen bass being stocked in June

ANY info on putting lime in a pond is very helpful to me. I've googled and googled but so many websites have different ways and different processes that don't explain the benefits of the lime


My main questions are:

What do I need to test for to know if my pond needs lime?

What is the best fish friendly lime?

Could I mix the lime with water and spray it from a small boat?

What are the main benefits of adding lime to a pond?




Sorry if these are too many questions, I really don't want to harm my fish

I have had to get pretty intimately acquainted with alkalinity since beginning to work in East Texas and I have done a lot of reading on the topic so let me take a swing at answering your questions here this morning.

1. An alkalinity test will tell you if you need lime. Easiest one I have ran across is made by Hanna. Its a little colorimeter and is super easy to use. Pretty accurate as well from what I have seen. It will measure in ppm CaCO3 typically. (Below 20= definitely need lime. 20-40= certainly wouldn't hurt if its in the budget. above 40= good to go)

2. You want agricultural lime, the finer the better. Ag Lime is just crushed limestone and is pure calcium carbonate (well probably not 100 percent pure). Where as hydrated lime is Calcium Hydroxide. Ag lime applied at appropriate rates (usually about 2 tons/ surface acre) will not harm fish by causing a dramatic change to pH. Hydrated lime will quickly and dramatically change pH and can definitely kill fish.

3. Best way I have found is using a little barge or stripped pontoon boat. Dump some lime on the front with a tractor bucket and use a 2 inch trash pump to mix it into a slurry and wash it off the boat as you drive around. This will give the best results. If you do not have access to this type of equipment, a spreader truck from your local coop will sometimes back up to several places around the pond and spread it as best they can that way. Even just dumping a pile in the way of runoff entering the pond will SLOWLY contribute to better alkalinity. Basically, the more of the pond bottom you can cover in lime the better your results will be. Results will not be instant. You will likely see the alkalinity slowly improve over a couple months following the treatment.

4. The main benefit of adding lime is improved alkalinity. Alkalinity is important for fish health, growth, and reproduction. Alkalinity also determines how available the nutrients in your pond are to the animals and plants within the pond. Nitrogen and phosphorous are more biologically available when alkalinity is improved. Liming can sometimes result in increased growth of aquatic vegetation so be prepared for that as well. Its also necessary for phtyoplankton production which is the beginning of the food chain in all ponds. I have seen a few ponds do surprisingly well at 10-20 ppm alkalinity but the exceptions probably shouldn't make the rule. We ran some impromptu experiments at our own brood ponds and it seems like 40 ppm was the sweet spot for us. We saw dramatically better growth and reproduction above 40 ppm so that has become our target in places that have chronic alkalinity trouble where the recommended 100 ppm may not be feasible. I ripped a few sections out of an old presentation of mine that may help explain lime and alkalinity and thier relationship to pH as well and copied them below.

"Alkalinity is determined by the amount of calcium carbonate in the water which acts as a buffer against rapid pH changes which can be lethal to fish. So, the variable we are really seeking to control with alkalinity is the pond’s pH. pH stands for potential hydrogen and is a measure of acidity, more specifically it is the negative log of the molar concentration of hydronium ions, but let’s stick with acidity for now. pH is measured on a scale from 0-14, zero being the most acidic and 14 being the most basic. This scale is logarithmic in nature, meaning that each increase or decrease of one whole point is a tenfold change to the acidity. So, when water changes from a 7 to a 6, it isn’t just becoming a little more acidic, it is becoming ten times more acidic! If it drops two points, that isn’t 2 times more acidic, it is 100 times more acidic! Looking at things this way it becomes easier to see why pH and alkalinity are important parameters to monitor.

Most fish can tolerate a wide range of pH levels from 4 to 10 because they can regulate their internal pH. However, this internal regulation requires time and energy. Shifting too dramatically can cause fish to succumb to pH changes before they have time to acclimate their bodies to the change. Even less dramatic daily shifts in pH can result in stunted growth rates due to the added stress and energy input required to maintain internal pH. This is energy in the form of calories not being converted to bodymass. Burning excess calories is cardinal sin when trying to grow giant largemouth bass. Ideal alkalinity levels in a pond are between 50-150 parts per million. At these levels, the water is adequately buffered against pH changes. At levels below 20 ppm your water lacks natural minerals such as calcium that fish need to survive and grow. At 40 ppm, we see Largemouth Bass thrive, exhibiting excellent growth and reproduction.

Throughout any 24 hour period, the pH of a pond will change regardless of the alkalinity. It will be lowest in the morning after the night’s respiration. This process of respiration we know consumes oxygen but it also produces carbon dioxide. Carbon dioxide when combined with water forms carbonic acid which lowers the pH of the water. This is why your dissolved oxygen and your pH will always be the lowest right before the sun rises. Once the sun rises, the plants and phytoplankton in your pond will resume photosynthesis. The process of photosynthesis uses carbon dioxide, which the plants pull from the carbonic acid in the water, and produces oxygen. This is why your pond’s dissolved oxygen level and pH will always be the highest in the evening . This daily fluctuation is normal in all ponds and is the reason alkalinity is important to prevent too wide of a swing."


Hopefully that helps you navigate the tannin stained, acidic waters of pond chemistry just a bit better.

Fred185,

Apologies, I'm a little late to the party here (saying spring time is busy in the fish business would be an understatement) but its sounds like Ewest already answered your question. If you wanted to be safe, you could always go with 4 tons/acre in the pond then lime the surrounding ground in the water shed as well. That way as your runoff flows over the ground it can be neutralized and carry some of that lime with it as well. If your rain is acidic and your soil is acidic you definitely have an uphill battle on your hands and you are going to want to lime everything you can lime.

Bradley I am basicly on the same topic and have a question for Bassquatch , Thanks,

Bassquatch,
I have a 20-year old 3-acre pond, filled completly by a valley water shed. I never gave water quality a thought when I started the project. I had to install a overflow pipe almost immediatly because of rain. At the time I did not understand rain was acid rain. I stocked the pond with 100 bass and the same amount of bluegills. Around the third year the first 5-pound bass was caught, and many more for the next several years. However the last five years a 3-pound fish is hard to catch. During the hunting season a otter was seen in the water. So I thought (after reading) that was the problem. However I stumbled on this water issue and followed up on it. I had a expert water test done for my home and pond in 2010 before the Marcellus Shale gas drilling started in my area in Pennsylvania. I went back and looked at the pond water PH done at noon and was 5.8. I did recent test and they are all -4. Being it is all rain water it was hard to believe until I looked at EPA rain map for my area and it is -4. The ground in the fields is 6. However as we are experiencing snow melt, the water entering the pond is -4. My question is ? would I have a problem dumping too much lime at one time. I know lime itself will not go higher than 7. But from 4 to 6 ? There is a huge fish population in the pond. They almost look like clones, healthy and about 2-pound. But the bluegills seem to have suffered. Years back they were like fluke, but small now. Thanks in advance Average between 6-8 feet, deepest 34 feet.