I recently made a land purchase that has a 4.5 acre lake on it. My first water sample showed alkalinity at 4. I added approximately 3 tons of ag lime. amendment based on The report showed alkalinity of 4. Neither the lake nor land had been managed, although the lake is overpopulated with bass.
The property is located in the piney woods of east Texas. The lake is completely surrounded by pine plantation. The water for the lake comes from runoff, primarily from one feeder creek. Being located in east Texas, I estimate that their is a fair amount of water flow through the lake at times. Right after the lime addition, we received almost 4 inches of rain. This has me thinking about methods to buffer the alkalinity in some way.
My question is, what can I do to help maintain the alkalinity in a desired range, short of draining this lake and starting over.

I plan to reduce the pine trees around the lake. Will that help?

I was also thinking of lining a long stretch of the creek with limestone base. I know ag lime is used to raise alkalinity, but lining the creek with it is not really an option. Would lining that feeder creek with limestone base be a waste of time and money?

Any suggestions are appreciated. Thanks

It is difficult to manage the chemistry of your pond water when you have a high rate of water passing through your pond.

Having TOO MUCH water is a much better problem than not enough.

Can you install any kind of gate in the feeder creek and divert water around your pond on most occasions?

If so, then you might be able to do affordable amendments on your pond.

Also, the pine needles going into the pond are certainly adding nutrients and increasing the muck buildup on the bottom. Clearing back some pines sounds like a good idea to me.

I believe the green pine needles probably also lower your pH (and worsen your water quality), but I am not sure on that one.

I have caught bass in forest ponds that had so many oak leaves that the water was permanently stained brown. Didn't know the pH, but it had to be low. You making improvements can only help your pond get better from here.

Good luck on your new (to you) 4.5 acre pond!

Tall Pine, given that your place is in the rainiest area of Texas, you might even consider draining the pond & starting over. You could put in good habitat, more ag lime (based on my experience in east Texas, you'll need it!), and restock purposefully toward your goals as the pond refills.

It would be possible to put in a gate in the feeder creek, but I don’t have anywhere to divert the water to. It would require constructing a ditch to bypass the the lake. It’s really not practical due to elevation, as the lake lies at the bottom of two hills.
I do think removing all pine trees and most of the other trees and vegetation from the perimeter can only help.
Thanks for the input.

Anthropic, although the lake needs some help it is actually not a bad fishery. I have caught two largemouth over six pounds this spring even though the majority of fish caught do not show size distribution. The majority of fish appear stunted due to over population. All of that to say I hate to drain the lake and start over. Finances are definitely a factor. My first priority has been to reduce the number of lmb, and restore the forage base and forage habitat.
I may just try adding a few 100 pounds of ag lime to the feeder creek periodically as it washes out or is absorbed. Then in a few months , have another sample ran just to see if t is making any difference.

Thanks for your suggestions.

Tall Pine - I'm not sure what you mean by "4" in alkalinity?
What's your pH? if it doesn't need/shouldn't be raised then don't add AgLime or Pulverized lime, use gypsum.

I went thru a number of the same problems but my pH was hella off so I got that up from 5.1 to 7.0 pH then addressed alkalinity using gypsum.

For both pH and alkalinity there are formulas to take a majority of the "Guessing" out.



Here's a good overview of what and how on alkalinity.
Alkalinity-and-Hardness-in-Production-Ponds

Here's my thread here on doing the adjustments. I'm taking samples in a week or so to see where the pond is at prior to restocking.
What to Test For: Old/New strip mine pond



As for taking samples/getting the report - I bought a test kit and for the price of two samples from my three ponds it's already paid for itself.

Recommend you take several soil sample from the watershed and send to TAMU for testing.
The 3 ton of ag lime you applied sounds way light to me. Generally you'll want to add lime at the same rate called for in your soil sample.

In my part of the world that amounts to 4 ton/acre repeated every few years to maintain pH around 6.

If it's possible for you to purchase and apply limestone cobble in the 4"-12" size range in a few place around the waterline
that will be long-term help. Doing the same in the stream bed that feeds your pond would also provide benefit long-term.

Stressless made a good point of differentiating between alkalinity and pH, and provided a couple links to reference material.

It's all about the dirt. Cutting some pines will not help a lot as its the dirt. Adding ag lime is the most effective cure. You need to determine how much water flow through you have. My guess is you need 4 tons per acre. Can you post your report? Get an inexpensive alkalinity test kit. There are thousands of ponds with your issues across the south from east TX to Ga.

Stressless, alkalinity result was 4ppm with PH of 8.2. I would post the report but can’t seem to figure out how. Newbie, lol. The only other parameter tested that was not in the listed optimal range was hardness, the result was 20ppm.

The suggested amount was based off of the information I provided, so amount of ag lime to add may very well be off. But that would be my fault, as I do not know the average depth. The surface acres are 4.5, with depth up to 22 feet. But, probably half of that is less than 4 or 5 feet.

Ewest, thanks for the input on the cobblestone. That’s sort of what I was thinking, but didn’t want to waste time or money on something that would be a waste of time. As far as flow through the lake, there is no way of knowing that since it is completely dependent on rainfall.

Thanks again for all the info. I’m learning from all of you that each lake is quite unique.

Not an expert here but lime is used in dirt to RAISE the PH, if your PH is 8.2 then it’s too high. 6.5-7.5 is the number most people strive to hit.

Alkalinity charts
See the second chart showing large pH swings in daily pattern with low alkalinity.

TallPine -

At 8.2 pH, and my advice based on lots of pro advice here on this forum is DO NOT use or add any more lime, limestone or crushed lime aggregate until you get your alkalinity under control. Your pH is good, you need really need to raise your alkalinity. What I was told and in the calculations above shoot high to 70-90ppm. So its just at the minimum after applying Gypsum.

Gypsum is the element that will do that, raise alkalinity and not raise pH, thats what I did in my pond, that had low but not REALLY low alkalinity like yours. In your first post you mentioned needing a buffer, thats exactly what alkalinity does for pH in a pond.

Best if luck, but it's not luck if you're lucky.

Adding this for folks that look up 'Alkalinity' on the forum and find this thread - as well as TP.

Alkalinity – excerpt from “Interactions of pH, Carbon Dioxide, Alkalinity and Hardness in Fish Ponds” by William A. Wurts and Robert M. Durborow, Southern Regional Aquaculture Center 1992

Alkalinity
The quantity of base present in water defines what is known as total alkalinity. Common bases found in fish ponds include carbonates, bicarbonates, hydroxides, phosphates and berates. Carbonates and bicarbonates are the most common and most important components of alkalinity. Alkalinity is measured by the amount of acid (hydrogen ion) water can absorb (buffer) before achieving a designated pH. Total alkalinity is expressed as milligrams per liter or parts per million calcium carbonate (mg/L or ppm CaCO3 ). A total alkalinity of 20 mg/L or more is necessary for good pond productivity. A desirable range of total alkalinity for fish culture is between 75 and 200 mg/L CaCO3 . Carbonate-bicarbonate alkalinity (and hardness) in surface and well waters is produced primarily through the interactions of CO2 , water and limestone. Rainwater is naturally acidic because of exposure to atmospheric carbon dioxide. As rain falls to the earth, each droplet becomes saturated with CO2 ; and pH is lowered. Well water is pumped from large, natural underground reservoirs (aquifers) or small, localized pockets of underground water (groundwater), Typically, underground water has high CO2 concentrations, and low pH and oxygen concentrations. Carbon dioxide is high in underground water because of bacterial processes in the soils and various underground, particulate mineral formations through which water moves. As ground- or rainwaters flow over and percolate through soil and underground rock formations containing calcitic limestone (CaCO3 ) or dolomitic limestone [CaMg(CO3 )2 ], the acidity produced by CO2 will dissolve limestone and form calcium and magnesium bicarbonate salts: CaCO3 + H2O + CO2 = Ca+2 + 2HCO3 - or CaMg(CO3 )2 + 2H2O + 2CO2 = Ca+2 + Mg+2 + 4HCO3 - The resultant water has increased alkalinity, pH and hardness.

Don't guess! You can have (as charts show) high pH and low alkalinity. See diurnal pH swings. Check the pH in am and afternoon and see what they are. The way to fix that is with ag lime to increase buffering and in so doing reduce high and low pH readings. If you have a constant 8.4 pH or higher then repost results and you may have too (but I doubt) use gypsum given your location. Last time I checked gypsum was much more expensive than ag lime. Use the right one based on results.

What is a good test kit? I see Amazon has many under $15 and some for several hundred dollars.

This is what I use.

LaMotte Alkanilty Test Kit

+1 on Lamotte test kits, think about the range of tests, alkalinity, pH, harness, etc, you should test, they make many different kits. Buying one kit that cover the range is much cheaper then individually buying each test kit.

Update on my efforts to address the low alkalinity. I added 3000lbs of ag lime, purposefully going a little below the recommended amount by Texas A&M since I was not sure about the average depth info I provided with that sample submission. I did purchase the Lamotte Test kit, and 3 weeks after adding the ag lime I ran a couple of samples. The results show alkalinity at around 6-7ppm. It is a little lower than I had hoped for, but we have had some heavy rains and there was some small flow through the lake at the time of sampling. All of this to say that I don’t think I would be able to keep up with adding enough ag lime as things are now. I believe that reducing acidic sources from the drainage (pine trees), liming the surrounding soil where those pines where, and then adding limestone base in the feeder and a few other areas for erosion control will only help my alkalinity battle. I will update this project on alkalinity in a few months, as I unfortunately can only work on this on the weekends and it will take me longer than I would like.

Also, alkalinity won't change overnight. Check it again in a few months. Just like adding lime to soils, here they recommend doing soil tests in the Fall and liming in the Fall if needed, so the soil pH will have changed by the Spring.

Adding lime takes time (couple months) to remedy alkalinity issues.

East Texas red clay soils are quite acid. Removing pine trees likely won't make much difference. We have to lime at the rate of 2 tons to the acre every 2-3 years in this area to keep a ph above 7. Regular ag lime is pretty slow and only about 55% effective per ton. Superfine
ag lime from Texas Crushed Stone in Georgetown is about 98% effective per ton. Being finely ground it reacts faster as well. We just got a quote of $70 per ton trucked to the Tyler/Kilgore area and dumped. We'll still have to get it spread in the lake.

I have a lined approx. 50,000 gallon Koi pond and show to have a ph of 9. Best way to lower the ph?

What time of day did you take the reading, and how old is the test kit? Have you checked any other water to verify if the test kit is accurate?

Update on my approximate 4.5 acre lake project and the alkalinity. The 3000 pounds of ag lime raised the alkalinity to 15-20 range. Can’t be more precise on that result due to the test kit I’m using. Added another 1000 pounds of ag lime in July and that barely made a difference in alkalinity. Sampling results with my field test kit showed alkalinity over 20. Maybe a little over.
Then the drought set in and my lake is down to about half its normal size. Water depth is down about 7 feet. My deepest area is now 15 feet. I have ran ph and alkalinity a few times over the last few months. The alkalinity has dropped a little but not more than 15. Ph still swings thru the day, but not as much as before. Ive gotten 7.8 to 8.5, 8.5 was during the hottest days when the lake was at its lowest.
I have not added any thing else since late spring out of concern that it would do more harm than good. The lake has taken a hit to the fish in it and I removed a lot of small bass throughout the summer. Despite the culling, I believe I had some die off and what survived did not grow much due to the conditions.
My short term plan is to continue raising alkalinity next spring once the water level rises hopefully. I would like to add about 5000 pounds of ag lime based on last years addition and result.
I know it’s not optimal, but if I can achieve a consistent alkalinity of 40-50 without ph swings, I will be happy.

Optimal, perfect, just right is something that I’ve never achieved. Pretty dang close is about all I’ve achieved in life.

It is easier to spread lime in pond basin when water is low, assuming you are not using a boat. Put most on the bank where water will be 2-3 ft deep when full.

Does Alkalinity in the water have to do with the area you are in or what ?
I was curious and pulled out my Water Report and it shows 110 ppm
That seems like a huge difference from what I'm reading here

60-150 ppm (mg/l) is desired for best fish growth (healthy ecosystem). 60% of surface water in KS is 100-300.
This is also a pH buffer to subdue wild swings ..
To better answer your question, yes, it has a lot to do with location, water source and what substrate that water flows through/over before it gets to pond.

Jason D. This is only pond or lake I’ve ever had, so I really don’t know for sure. I’ve thought it may be due to the amount of pine trees. I know pine needles make the soil acidic, so that water going into my lake is also acidic?