Your pond has pond sludge, and this might not be a problem. A little bit of sludge is inevitable, but if you your pond has too much it can get to be a big problem fast. The problem is that this sludge tends to be mostly impenetrable to oxygen, depending on how thick it is. The lack of oxygen inside of it means that anaerobic bacteria reign, and their metabolisms produce hydrogen sulfide. Hydrogen sulfide is the stuff that makes that rotten egg smell when you stir up your pond bottom too much or clean out your filter after leaving it too long. It’s toxic to the other living things in your pond, which means that too much pond sludge can start to kill off other things, starting with your beneficial aerobic bacteria and algae, which means more dead things that are making up the sludge (and less aerobic bacteria working to eat the sludge from the outside), which means more hydrogen sulfide, which kills more things, even, in bad enough amounts, your plants and fish. The sludge also tends to form an oxygen-sealing layer along the bottom of your pond, which can smother and kill the slimy layer of healthy algae on the bottom of your pond, leading to even more problems.

As you can probably see, this can turn into a runaway problem, especially in smaller ponds with more delicately balanced ecosystems.

So, how do I control the sludge?

The first step is preventing the sludge from building up too much. You can do this in three ways: physical, biological, and chemical. The physical route means keeping sludge-forming debris out of your pond. Few things do more for this than a good pond net over your pond in fall and winter. You should also take care to keep things like grass trimmings from straying into your water, as well as making sure that fertilizers and other lawn chemicals don’t find their way in. You’ll also want to trim back and remove dead and dying plants in your pond to keep them from falling to the bottom and rotting. Keeping stones on the dirt of your pond plants to keep your fish from digging them up can go a long way, too.

The biological route means keeping your pond stocked with healthy aerobic bacteria, be it in a biological filtration system or just loose in the water. You’ll also want to keep your slime layer of algae healthy (for instance, I don’t ever recommend power-washing the bottom of an established pond). The chemical way of preventing pond sludge is to keep the most important thing for a healthy pond flowing: oxygen. This means aeration (which, for my money, is one of the best things you can do for a pond to keep it healthy). An aerator adding oxygen to the lower levels of your pond will keep your slime layer and aerobic bacteria healthy, as well as keeping the sludge layer from forming a seal to keep out oxygen.

The second step in treating pond sludge is physically removing as much of it as you can. This can mean just reaching in there and grabbing the black crud, pulling it out, and getting rid of it. It’s not pleasant (though it is oddly satisfying), but if your sludge problem is bad enough there may be no way around it. Either way, you’ll probably want to get and use a good pond vacuum, as your hand just isn’t a good enough tool to get rid of the sludge that’s in between rocks or loose in the pond. It’s pretty easy work, vacuuming a pond with good equipment, and you’ll be amazed at how much difference getting rid of most of your sludge and debris will make in both water health and how nice your pond looks. Keep in mind that you’re never going to get rid of all of your sludge (see above, re: “your pond has sludge”), but you can certainly keep it well under control with just a little bit of work.

Finally, if you’ve developed a sludge problem, you’ll want to add extra beneficial bacteria get your pond back on track (even after you’ve physically removed it). I’m a big fan of Biocuda Biomax bacteria additive, which has not only healthy bacteria cultures but also activated barley in one additive.

Photo by Jrwooly6

Spring means the perfect recipe for algae blooms in your pond. The water temperature is rising and the sunlight hitting your pond is increasing. The planktonic algae (free-floating, single-celled algae) that turns your water to pea soup loves sunlight and warm water. And, because it’s single-celled algae, it grows and reproduces to take advantage of seasonal changes very, very quickly, much more quickly than your pond plants do. Since your pond plants are just waking up from their winter naps, they aren’t using as much of the nutrients in the water as they will later in the season. Their leaves also aren’t shading nearly as much of the water surface. This means lots and lots of happy nutrients and sunlight for that planktonic algae.

So, how do I deal with it?

Well, dealing with planktonic algae should usually be a multi-pronged approach. The first thing you should probably try to do is to choke off the nutrients that are feeding the green goop. Here are a few things that you can look at to see if an abundance of nutrients is your problem:

• Overfeeding fish: this is one of the biggest things that I see. Whenever you feed your fish (if you do at all), make sure that you’re only feeding them what they actually eat before it starts to sink or get sucked into your filtration system. 
• Buildup of organic material in the pond: Do you use a good pond net to cover your pond in the fall? You should, but even if you do, you’ll still probably need to clean out excess leaves in late fall or early spring. This can also mean that your pond planters aren’t covered with sufficient gravel or stone to keep the dirt out of the water.
• Too many animals around the pond: The biggest culprit is birds. A flock of geese or ducks around your pond will pollute it with a lot of droppings, and that can throw your water balances way off. Also, having bird feeders too close to your pond means both droppings and stray birdseed in your pond. Also, if you have pets, make sure that wherever they eliminate their waste doesn’t drain into your pond. If it does, try to keep it as clean as possible.
• Too few plants: This isn’t a problem that I ever have, but if you don’t have enough plants to absorb the free nutrients in the water, that can cause problems.
• Not enough algae: This may seem counter-intuitive, but if you don’t have algae in your pond, it will never find the right balance to naturally keep itself clean. What you want is the nice layer of attached algae that accumulates naturally and coats the bottom of your pond and stream. This attached algae will use up lots of the free nutrients in your water, keeping it healthy and clear. This becomes a big problem when people over-clean the bottoms of their ponds, scraping or power-washing away the natural patina of algae that their ponds have developed.

Photo by Orin Zebest

Besides addressing the causes of the planktonic algae, there are two big equipment-related things that you can do to deal with the algae. First, make sure that you have a good biological filtration system installed in your pond, and keep it healthy. This will both directly filter out some of that free-floating algae and use up more of the nutrients that are causing it. Second, you can kill the algae with the power of light. A good UV Clarifier system works essentially the same way that a lot of places use to clean their water of algae and bacteria for drinking, blasting the water with enough UV light to sterilize it. This can be highly effective in killing off the free algae in your pond.

Do I need to fertilize my pond plants?

Not always. It can depend a great deal on the quality of your water, what’s in your pond, etc, just like in a garden. If you fertilize carefully, though, most pond plants are improved by fertilization.

Can I just use regular garden fertilizer on my pond plants?

I strongly discourage this. Regular fertilizers can be extremely harsh, and aren’t formulated to avoid harming your pond’s ecosystem. They can cause major problems, from huge algae blooms to killing plants and fish. Further, they’re not usually in a form that can be delivered to the soil of the pond plants without seeping into the water. I recommend a specialized pond plant fertilizer from a reputable company, such as Aquascape. I’ve also been impressed lately with Laguna’s plant fertilizer spikes, which have the neat feature of being activated by temperature so as to only fertilize the plants during growing months. This takes a lot of the guesswork out of timing fertilization (which, as those pond owners affected by the cold spring that much of the country just experienced can attest, can be tricky).

How important is it to bury tablet fertilizers thoroughly?

With just about any pond product, I of course recommend following the included instructions very carefully. This one, though, is especially important. If the fertilizer tablets aren’t completely covered by the soil, they will leech fertilizer into the water, which can give you some pretty serious problems with algae (especially planktonic algae, the free-floating, single-cell stuff that causes pea-green water). Also, be sure that your underwater plant beds are covered adequately with stone to keep your fish from digging up the fertilizer tablets.

1. Thermometer –  Here are some key temperatures:
   Constant 50 degree water temperature – you can start feeding fish (cold water food)
   60 degrees – regular feeding
   70+ degrees -  move plants back into your pond if they were removed for winter
2. Pond Net –  - A sturdy net is a must to remove bottom debris from your pond
3. Filter Media – Spring is a good time to replace this if needed.  Aquascape’s Bioballs are also a great way to supplement your existing filter media.  They’re designed to provide a perfect home for lots of beneficial bacteria.
4. Sludge cleaner –  It makes spring clean-up much easier!
5. Declorinator –  A partial water change in the Spring is something we highly recommend.

What you need to help keep your pond in tip-top shape through the cooler months is a specialist. Our Cold Water Beneficial Bacteria from Aquascape will help. It contains seven different strains of concentrated bacteria colony-forming units that thrive in temperatures below 50 degrees. It’s safe for fish and other pets, of course, but it does a great job of reducing organic debris in your pond as well as nitrates and ammonia that can really build up in the colder months without active bacteria colonies. Adding this bacteria is a relatively inexpensive step that can go a long, long way toward a cleaner, healthier pond year round.

OK, it’s possible that I was lazy and just took a picture of my pond as it is and made it look super green with Photoshop… So sue me.

When your pond water is green (and it isn’t St. Patrick’s day) it’s most likely because of single-celled algae.

The green color comes because this kind of algae remains suspended in the water. When the conditions are right in a pond with lots of sunlight & nutrients, as many as 5 million (!) algae cells can be in each milliliter of pond water (that’s only 1/30 of an ounce).

These organisms are obviously very tiny.  They’re so tiny that they’ll go right on through even very fine filters.

The trick is to use a flocculant to help filter them out. Flocculants make the small particles stick together so that they’re large enough to be caught in the filter. I really like the new Rapid Clear fine filter pads. They’re a disposable filter from Aquascape made to be used with a flocculant.

Be careful, your filter pads will clog pretty fast. When I use a flocculant I also like to use a sludge and filter cleaner, too.  The bacteria in the sludge cleaner tracks down those chunks of algae and eats them.

Once things are back under control, I keep them that way with a regular use of beneficial bacteria (the dry is what I recommend for regular maintenance since it is the best bang for your buck).

• Spring- the fluctuation in temperatures can be very stressful on your fish. (those who have wintered in your pond especially!) Two ways to help with the stress. When your going to have a cold snap, turn your fountain or waterfalls off to slow down how fast your pond water cools. Add pond salt to help develop a healthy slime coat on your fish. This helps the fish naturally fend off any bacterial infections and parasites.
• Summer- The perfect pond water should be in the range of 68  to 74 degrees Fahrenheit. Water loses much of its ability to hold oxygen when the temperature is above 85 degrees. Your fish won’t be able to breathe. This is when aerators, fountains and waterfalls help oxygenate the water. (Higher oxygen levels also decreases algae growth!!)
• Winter- Your fish’s metabolism slows when your water cools down. They don’t need to eat when the temperature stays below 39 degrees Fahrenheit. An easy to digest food is suggested if the water is above 39 degrees. If you live in an area the your water freezes, keep part of your pond open so that the toxic gases can be released. A de-icer works well. Don’t break the ice to keep an open hole, the shock waves through the water can hurt your fish.

Water temperatures shouldn’t change more than 5 degrees per day to keep your fish in their best health. To monitor the water, a good thermometer comes in handy.

When the  leaves get into your pond and start to decompose tannins leach out, making your water a different color.  Interesting facts:

• The tannins from decaying leaves and vegetation by a stream can make what is actually called a “blackwater river”.
• Peat tannins (from bogs) can turn the water a brown color.
• When tannins are in your pond they can make the water smell (and taste) bad.

Once the water in your pond has been stained by tannins, just like a cup of tea – the color will not “settle out.” They will have to be chemically or physically taken out. Step one is to take out the leaves from the pond with a net. This means both floating and the ones that have settled to the bottom. Don’t forget to empty your skimmer net regularly. It’s like a giant tea bag, seeping more discolored water.

I’ve found the most effective, fish friendly way to remove the color from the water is Activated Carbon. Put the carbon where there is strong water flow (mine is in the skimmer). The tannins are absorbed by the activated carbon. Once the carbon has absorbed it’s limit, it should be taken out and replaced if needed.  If your water is very discolored, a partial water change might be needed.

Here are a couple highlights:

1.  Ensure good water circulation across the probe.  One sign that you’re not getting enough water circulation is scale continuously building up on the probe.

2.  Maximize the life of your IonGen probe by only turning up the power level as needed.  You can also shut down the IonGen during the winter when it isn’t needed.

3.  Check the probe every spring to see if it needs to be replaced (the images in the video will show you what this looks like – you can order the IonGen replacement probe here).

4.  If you notice uneven wear on the two bars, it may mean that the probe isn’t installed in the proper direction in the flow chamber.  The small red dot on the top of the probe indicates the correct direction (the water should be flowing between the two bars).

Click here to view the embedded video.

General Characteristics

Spirogyra are comprised of cylindrical cells that are connected end to end, forming a long, thin, green filaments. This algae is commonly found in fresh, clean water and tends to grow in large, slimy masses. In the spring, the spirogyra begin life underwater, though as the water warms, the plant produces large amounts of oxygen, which becomes trapped in the filametous masses. The trapped oxygen gives the tangled mass buoyancy and thus the tangled filaments rise to the surface in one large mass. Different species can grow and become entangled in the same mass.

Where it Comes From

Spirogyra reproduce both sexually and asexually, releasing spores into the environment. String algae spores are extremely durable and can remain dormant in the environment for many years becoming active after being introduced into water. This is why backyard ponds can be blanket weed free for years before becoming infested. Unfortunately, removing the algae actually releases more spores into the environment, increasing the chances that your pond will become infested again within a matter of days.

Removing Spirogyra

Spirogrya proliferate quickly under the right conditions, quickly becoming unmanageable. The main problem with a string algae infestation is that, if left unchecked, it can quickly deplete the pond of vital oxygen, strangling ornamental plants and fish. Fish can also become entangled in the algae, causing death. Plus, it just looks bad.  For these reasons, blanket weed must be removed from your pond.

• Manual removal: The easiest method for removing string algae is by pulling it out. However, this method is extremely ineffective for long term control. Manual removal of spirogyra releases spores into the environment, which will cause another infestation within a couple of days.  This method is good for removing the big chunks before you apply beneficial bacteria.

• Algaecides: There are a number of chemical solutions available to help control string algae as well; however care must be taken to prevent harm to other plants and aquatic life.

• Limit growth naturally: One of the most effective ways to treat string algae is to create unfavorable growing conditions. Creating artificial shade sources to limit your pond’s exposure to direct sunlight as well as adding oxygen to the water will help stunt growth. Also, you can introduce other plants into your ecosystem that will compete with the algae for food and other resources. Reducing the number of fish in your pond will also help since string algae thrive on fish wastes and uneaten fish food. Installing a large biological filter and seeding it with beneficial bacteria will also improve the water quality in your pond and reduce the chances of a blanket weed infestation.  We recommend Aquascape’s SAB (String Algae Buster).

“Neglect your watery haven and it could quickly become a stagnant hell” -  words from Andi Clevely over at mydeco.com.  She has some tips for keeping your pond in balance and looking great.  I especially like these tips for feeding plants:

Established deep–water and marginal plants may need feeding when growth resumes in spring because nutrients easily leach from the soil or compost into the pond. Feed them cautiously to avoid enriching the water further and stimulating algae growth.

Use a slow–release fertilizer applied direct to individual plants, and where possible choose one that is seaweed–based. Do not over–apply, and never feed floaters and submerged plants.

Image Credit: Steven Wooster

If you’re looking for an awesome water lily or lotus plant, head on over to our pond plants section.  Most of the pictures you see on this blog are plants from the same nursery, including this awesome pink lotus wallpaper.