Correcting Total Alkalinity

Baking Soda makes a safe cost effective alkalinity booster.

WHY: Total Alkalinity is a measure of the carbonates in the pond.  They are essential to creating an environment where beneficial bacteria flourish and fish stay healthy and grow rapidly.  Many people are blessed with high natural total alkalinity, some are not.  Those who live out on the plains, the desert south west, California, in limestone valleys, or otherwise hard water are generally among the blessed.  Those of us who live in the mountains, or near the top of a ridge, on the east coast, or otherwise have soft water, not so much.

TESTING:  It easy to find out your total Alkalinity using our Microbelift 5 in 1 Test Kit. The goal for Total Alkalinity is 100 mg/l.  If you have more, great.  If you have a little less, it’s not terrible.  If your readings are down in the 20s, 30s, 40s, you really need a fix.

RULE OF THUMB: For backyard ponds, add 1 pond of Arm and Hammer Baking Powder, yes the kind you use for baking, to raise the total alkalinity of 3300 gallons of water by 20 mg/l.  If you need to raise it more than 20mg/l, add this quantity every day until to get to the desired level.

EXAMPLE:  If you have a 3300 gallon pond and it tests at 20 mg/l and you want to take it to 100 mg/l, add 1 pound of baking soda a day for 4 days.

RULE OF THUMB: For farm ponds, add 1 ton of crushed limestone for each surface acre of pond.  For a more exact dosing recommendation, consult your local Agriculture Extension Agent in your County for directions to have the pond water or its sediments tested. For small earthen ponds with a limited flow through, you can also use Arm and Hammer Bulk Sodium Bicarbonate (ag grade baking soda), in the same quantities as you would use crushed limestone.  Unlike crushed limestone, it will dissolve immediately and give an instant boost to your carbonate.  As with backyard pond applications, if you are raising the total alkalinity more than 20 mg/l do not add more than will change the water by 20 mg/l per day so to not to shock the aquatic life.

Should I overwinter pond barley straw?

Overwinter pond barley straw below the ice.

Another question I get a lot during the winter months is this: If I leave my barley straw in my pond over the winter, will it still be good in the spring?

Yes! The bacterial cultures that make Barley straw effective will again become active as soon as the water warms up to above 40 or 50 degrees. Like all other processes in the pond, biological activity that occurs with barley straw slows down in the winter and regains efficiency with the coming of spring.

However, there’s a catch. With the increase in temperature, sometimes algae can grow faster than Barley Straw is able to keep up with. So although it may seem like your over-wintered straw is losing its functionality, it is really just being overwhelmed by a temporary algal growth. But this is not entirely a bad thing. Many fish and other aquatic creatures rely upon this initial flush of vegetation as their first post-hibernation food source, like a spring tonic. Unfortunately, as the season progresses, they will abandon this source in favor of better, more nutritious food. Finally, once water temperatures regularly exceed 50 degrees, bacterial growth will begin to take over and the algae will once again remain in submission.

Algae is growing ON my barley straw. What’s wrong?

If there is algae growing ON your barley straw, something is amiss.

Barley straw is added to ponds to retard the growth of algae.  So, it definitely should not be growing ON the barley straw.  What gives?

I get a few of these inquiries each spring. Barley straw that is well colonized by beneficial bacteria will greatly retard the growth of algae in the water surrounding the straw and there should be no algae growing on the straw itself.  If there is, something is definitely out of whack.

What can cause this failure?

The number one reason for this in the spring time is that the water has just warmed to the 40 to 45 degrees range, warm enough for the algae to start growing but not warm enough for the bacteria to develop sufficiently to block growth.  This problem will take care of itself once the water temperatures stabilize over 50 degrees.  So, patience here is the best cure.

The second most common reason is that the water does not have enough carbonate to support a thriving population of the beneficial bacteria.  The water is too ‘soft’.   This is a common problem on the East Coast and up in mountainous regions.  This is easy to check for and easy to fix.  If you suspect this is the problem, test your pond water for ‘Total Alkalinity’ using our Microbe-lift 5 in 1 Test Kits. If the level is below 100 mg/l, supplemental total alkalinity is needed.  See my blog on correcting Total Alkalinity if this is the issue.

The third most common reason in small backyard ponds is that the water has been allowed to concentrate nitrate to such a degree that no amount barley straw will work.  To check this, use either our Microbe-lift 5 in 1 Test Kit or our Microbe-lift Nitrate Test Kit. Test in the morning and afternoon over a period of several days. If your levels are consistently over 5 mg/l, you really need to lower your nitrate level.  This can most easily be done by doing one or more water changes.

The last possibility is that the pond has been dosed with chemicals that have killed off the beneficial bacteria which need to colonize the straw (as well as your bio filter).  Review your pond management practices and stop using chemicals.

Winter is a good time to lime your frozen pond

Frozen ponds are an opportunity to lime

If your pond freezes enough in winter you can spread your lime right over the ice

If you own a pond, you know the importance of liming. And if you own a pond in the far north, you know the nuisance of seeing your pond turn into a Popsicle. However, your pond-turned-ice-skating-rink has a special benefit that no other region does: You can lime it without the hassle of distribution.

If you live up north, and your water has been acidic (below a pH of 7.5) or you have a low Total Alkalinity (below 100 ml/g), right now is the ideal time to lime.  Fostering overall pond and fish health, liming definitely supplies the “biggest bang for your buck” for any pond practice. (And I don’t even sell it, so I’m not just trying to sell you lime)

Crushed limestone is cheaper than dirt. It can be purchased in 40 – 50 lb. bags from your nearby farm supply store for about $3 or $4 a bag, and even less if bought in bulk (ideal for large ponds).  Buy crushed or pulverized limestone, not hydrated lime (hydrated lime can kill your fish)

What prevents most people from liming is:

  • Weight:

o   You will need approximately one ton per acre (but check with your local Ag Extension Agent for the exact amount required for the soil under your pond)

o   If you have an acre pond, you can’t use your trusty ½ ton pickup truck, so you’ll need it delivered

o   One ton = 40 – 50 bags

  • Distribution:

o   Lime can’t be dumped all in one spot. That’d be too easy. It must be distributed evenly throughout the bottom of your pond, just like you would lime a garden.

o   A small boat or barge (a kayak or canoe is not the boat for this!) will suffice for this task, if the weather is warmer, however…

o   If you live up north, you can simply walk across the ice, distributing as you go.  All you have to do is wait for the ice to melt and the lime to sink for the process to begin.  Easy as pie.

So, for all you northerners, your job has been made drastically easier. Finally, a good liming will last for several years.  And whoever thought you’d benefit from that big old ice cube on top your pond?

Winter is a good time to freeze out pond weeds

Pond Milfoil

Eradicate rooted pond weeds by freezing the roots

Winter has finally arrived. You’re curled up by your wood stove with a good novel and perhaps a mug of hot chocolate.  You mull it over: holidays are coming; family will soon be here, the joy of the season is settling in. Your pond, which may have iced over already,  is the furthest thing from your mind.

Isn’t that a lovely story? Unfortunately, there is one thing that could be done now before you can settle in for your long winter nap: Pond Weeding. You know what I mean – those pesky, tangled mats of vegetation that take up residence in around your pond each summer. They’re ugly, they’re unpleasant, they tangle fishing lines, they gross out swimmers and they’re embarrassing.  But are they preventable?  Yes.   All you need to do is start now.

There are a couple approaches to this task, and most of them suck. You can wait until they appear again next summer then get out a weed rake and cutter and start hacking at them yourself, if hard labor is how you want to spend a summer afternoon.  You can try sprays, but these are both scary to use and very bad for the environment.  Too little spray and you’ve wasted your money, too much and your fish will be floating belly-up.  Another solution is grass carp, which are effective, but illegal in many states.  So what works?

The answer, as usual, is simpler than one might think: Freezing.

Freezing can work for you if:

•             You live far enough north that ground freezes six to twelve inches deep in the winter


•             You can draw down your pond’s water level and maintain it at that point for 30 days

The basic concept is to freeze the root systems of pesky underwater weeds so they can’t send up new sprouts in the spring.  Small, soft plants such as water milfoil, naiads, water violets, etc. have a shallow root system and can be removed quite easily.  Larger plants, especially those with tubers such as water lilies or particularly resilient cattails will take some more time.

Lowering the water level to freeze the bottom might sound dangerous, but if done correctly it poses no harm to your fish.  Here’s how:

  • Lower the water enough to expose the pond bottom in the zone that grew weeds last year.
  • Leave a pool of water deep enough so that your fish have room to survive without risk of being frozen

The above two goals may result in a compromise between the two for shallow ponds.  If so, always err on the side of protecting your fish.

  • Keep the water level low for one month
  • Aim for the coldest 30 days of the year

§  For the mid-Atlantic, that’s January to February

§  Further south, that’s December to January

§  Further north is a different case; aim for the coldest snow less month.  Snow tends to insulate, slowing the freezing process

Finally, sit back, enjoy your hot cocoa, and think about how glad you are that all your pond weeding is done for next year.

Barley Straw, Barley Straw Pellets, and Barley Straw Extract: Which is best for my pond?

So much barley, which to use on my pond?

These are three great natural products and each has its place.  All are completely safe to use in ponds populated by fish, frogs, dogs, kids, livestock, aquatic plants, etc.:

o   Pluses: In most of the country, bales need only be replaced once a year; in tropical Florida and the Southwest they may need replacement every 6 to 8 months.

o   Minuses: The down side is they are chunky and hard to hide in the pond and need hard water to work optimally.   It’s not that they don’t sink with time, but that they are going to be visible at the surface for several weeks until they get wetted enough to sink.  And yes, a little straw residue is bound to flow off and clutter up the pond surface, again until they sink.  If your heart is set on natural straw bales but you need them invisible from day one, as the National Park Service does with our bales, you can wrap them in plastic mesh and weigh each one down with a 100 lb. of granite or other weights.  Yes they’re that buoyant at first.  If you can be patient, they will sink on their own in time.  As with all biological (bacteria dependent) treatments, they take several weeks to begin to work and do best when the water has at least 100 mg/l of total alkalinity.

o   Costs: In most areas, you can treat an acre pond for under $300 for the entire year. A six pack of bales, enough to treat an acre pond of any depth, including shipping anywhere in the Eastern and Central Time Zones is $225, or with bags included $260.  Add $10 per bale for shipping to the Mountain and Pacific Time Zone.

  • Barley Straw Pellets are less obtrusive looking but are more expensive, need replacing more often, and are pickier about where they will work.

o   Pluses: Barley Straw Pellets come in 25 lb. buckets and 40 lb. bags.  To apply, just walk around the pond and broadcast them over the shallows, or spread from a small boat.  They do sink immediately.  They are less expensive to use than Barley Straw Extract but more expensive than natural barley straw.

o   Minuses: Barley Straw Pellets, as with all biological (bacteria dependent) treatments, they take several weeks to begin to work and do best when the water has at least 100 mg/l of total alkalinity.  They are also best used in pond with hard bottoms as they tend to sink into the sediments in mucky bottomed ponds.  Once covered by muck, they are no longer functional. They tend to make the water a little more acidic.  This is a plus is you have very alkaline water but a minus if you water is already acidic.  They need to be replaced every 6 weeks.

o   Costs: $1416 per year assuming 6 month warm season. 120 lb./acre/6 weeks = (3)40 lb. per bag/acre/6 weeks @ $118/bag, delivered = $354 x 4 times per year = $1416 per acre per year (assumes 6 month warm season).  If you have a 1/6 pond, an annual cost of $236 may be acceptable, but if you have an acre pond, the cost of $1416 may be too much.  For that price you can install a complete Vertex Air 1 Aeration System (assuming you have electric available to the pond).

  • Barley Straw Extract is the easiest to use and the stealthiest.  The extract is a clear liquid that is simple poured into the pond. It is also the most costly.

o   Pluses: Works Great! So easy.  Just pour it in.  So unobtrusive, as a colorless, odorless liquid, no one will know it’s there.   And, because it is not bacterial, it begins to work immediately.  Barley Straw Extract is not picky about alkalinity levels or bottom sediments, as are the pellets.

o   Minuses: Barley Straw Extract needs to be applied every week for the first three weeks then every 3 weeks thereafter.  So, if you are not good a remembering maintenance chores, this may not be the one for you.  And, it is pricey for big ponds.

o   Costs: $2800 per average acre pond (6 foot deep) per year (assuming 6 warm month warm season).  You could install two complete aeration systems for that price.  But, if you do not have electric at the pond this might work for you.  Most of the barley straw extract I sell is for backyard ponds or earthen ponds less than a quarter acre.  But folks with big ponds do ask about it, so here’s the cost.  Here is an easy to remember rule of thumb: figure about $250 per million gallons per month.  A one acre pond, 6 feet deep is about 2 million gallons.