I would like to share some interesting successes I have had in
cultivating aquatic plants during the past year. First some
historical information. Like most of us, I had trouble growing healthy
aquatic plants until I tried CO2 injection, which
enabled me to keep almost any plant alive, though not always in the peak
of health. Addition of a micronutrient supplement
containing chelated iron increased my success, but I was still far from
growing anything like the beautiful
tanks seen in books. Some plants were still growing quite slowly, and I
was carrying on a continual battle with algae.
A little less than a year ago a friend suggested trying some locally abundant loam in place of my rather sterile substrates. He was using it in pots placed under the sand. He also suggested pushing pieces of broken lily pond fertilizer tablets into the loam. Being too lazy to replace the substrate, I decided to try the fertilizer tablets alone in a particular tank with sand-over-potting-vermiculite substrate. The result was an amazing growth spurt for most of the plants, which was slowed only when I forgot to add iron for a few weeks. During this period the nitrate levels measured in the 10 ppm range, indicating that the tablets were leaking into the water column. Algae were still growing strong during this period.
At the time I had done some reading on plant-soil relationships and was eager to try the loam, since it had a high cation-exchange capacity and was fine-grained (which would provide intimate root soil contact), both of which are excellent substrate qualities for plant nutrition (given that sufficient aeration exists). I set up a ten gallon tank using about a quart of the loam mixed with enough potting vermiculite to make a one inch layer, and covered it with an inch of sand. It was planted densely with a variety of plants, had CO2 injection and micronutrient additions, and 45 watts of full spectrum lighting. Over the time spanning the first month (starting on the day of planting) I probably added the equivalent of 50 grams of pond lily tablets (just a guess really).
The result was absolutely amazing. The plants grew huge leaves with great frequency, and many of the plants which I previously thought were suitable for a ten gallon tank quickly outgrew the tank. Plants with runners were extremely prolific. Grassy field of Echinodorus tenellus grew in quite quickly. The best think about this tank is that it has ABSOLUTELY no visible algae. A soft, non-tenacious green algae did grow in within the first few weeks, but as the snail population caught up, these disappeared completely. I had never had a tank which was absolutely algae free before this, and all of the plants used were from tanks with algae problems (i.e. the new tank had been well supplied with starter algae). Moreover, since the initial setup, plants have been moved to this tank from algae infested tanks and algae growth ceased to be a problem for them. The tank actually repels algae! I couldn&rsqo;t believe that I was afraid of adding nitrogen and phosphorus for my plants for so long because conventional wisdom that said it would only contribute to my algae problems. In this tank I had an example where they had done no harm, and possibly much good.
I have since set up two additional tanks according to the methods outlined below, with similar success stories, except that one still has some visible algae (buy nothing worse than before the addition of the N and P). Several people from the U.C. Davis area, and others from the internet who saw an older version of these instructions posted on the *.aquaria newsgroups have claimed the same successes that I found (including patchy algae successes), so I am confident that the method works reliably and is easy enough for relative beginners (which TAG readers are certainly not, so bear with the obvious items that follow which are included for the sake of completeness). The instructions are meant to be used as a practical guide to setting up planted aquaria as cheaply as possible with almost guaranteed success, and do not include mention of more advanced or expensive techniques which might be used with great success by some advanced aquarists (e.g. heating cables). More detailed information on soil/plant relations and nutrition may appear in a later issue of TAG.
I should mention that it seems to me that substrate aeration is not needed for the tanks that I set up, but they are all fairly young. The two-level substrate I use seems to allow an aerated space on top with lower nutrients and a rich, fine grained low aeration section on the bottom for those roots which care to penetrate. I should also mention that the internet is another great place to get accurate (but not always accurate) aquatic plant info besides TAG. A wealth of information is available from the World Wide Web site http://www.actwin.com/fish/, which contains mainly archives of quality postings to the *.aquaria newsgroups from the past. Now here is an outline of how I set up and maintain healthy tanks cheaply and easily, listed by subject.
If you’re lucky enough to have a 55 gallon or close-sized tank, good
lighting can be quite cheap. Our local hardware
store sells Liteway shop-lite fixtures which hold two 4-foot fluorescent
bulbs for $8.99. I use two of these fixtures
(holding four 40 watt bulbs total) over my 55 gallon tank, with Phillips
F40D bulbs ($3.99 each locally) in them. (Many
people say that they can’t fit two fixtures over a 55 gallon
tank, but the brand Liteway is only 4-1/2″ wide and a
pair fit nicely just laying on the cover glass. Other brands I have
seen are unfortunately wider.) This setup satisfies three
important factors for aquarium lighting:
daylightlights. This means they match the spectral output of sunlight closely, which the F40D does. The correct spectrum is obviously important for photosynthesis, as plants have evolved to work best with the sun’s spectrum.
Cool Whiteand other cheap $0.99 bulbs won’t look as good and might not work as well since they differ considerably from sunlight, but they can grow undemanding plants and some people claim that the difference in growth rates is minuscule. Also, don’t buy the EXTREMELY overpriced bulbs sold by aquarium specialist companies (up to $30), and don’t be fooled by the fact that
daylightbulbs don’t look as bright as
cool-whitebulbs, since cool-whites put out the highest intensity in the frequencies where your eyes are more sensitive, which are not the most useful frequencies for photosynthesis. Any
full-spectrumbulb will do.
green-wateralgae in the past with 2 daylight bulbs and two cool-whites over my 55 gal, which some people say is a clear sign of too much light) so I have adjusted the intensity down a little in the past by putting strips of tissue paper between the lights and the glass cover when algae have gotten bad. This is better than just using 2 lights with no light blockage, as you don’t sacrifice item (1). However, algae are often a sign of other problems which are correctable (see algae section). In the end I have always removed the tissue blocking the light after the algae is cured, to provide the plants with as much light as possible.
My experience tell me that you should spend your money on (1) and (3) and not spend too much on expensive special-spectrum bulbs. Finally, if you have the money, buy a timer to turn the lights on and off at regular 12 hour intervals, so the plants won’t get confused if you’re not home to turn the lights on and off at the correct time, or are on vacation. These run about $10 at our local hardware store. If you have a small or odd sized tank, the hood that came with the tank will satisfy neither (1) nor (3) above. That’s ok, just buy plants that do not require a lot of light. As a general rule, dark green plants are ok with low light levels, and light green or red plants need high light. If you can afford it, add a second light fixture to the aquarium so that there are two light strips above. You will notice a marked improvement in growth. I have modified some fixtures to fit three 15 watt bulbs over my ten gallon tank, although the plants could get by with two. The intensity of fluorescent bulbs goes down dramatically in the first 6 months of use, so having a lot of wattage means that you don’t have to worry about replacing the bulbs every 6 months (I use them until they burn out, but you may have greater success if you replace them more often, and not all at once). Having the tank in a bright indirectly lit room (not in direct sunlight) will also help.
This is not a big issue in planted aquaria as long as you don’t have TOO many fish. The plants love to absorb any waste products, including ammonia, that the fish give off, so you don’t need huge cultures of nitrifying bacteria. Filters serve other purposes though:
I use Hagen
Aqua Clear back filters for my aquaria. Any filter
that uses an electric motor (not air bubbles) and is not
an undergravel filter will do. Canister filters are supposed to be good
These are sometimes unnecessary in warm houses, but they’re cheap so you might buy one anyway and set it at 74 Fahrenheit. Temperatures near 80F are too hot for plants, and should be avoided unless the fish cannot acclimate to lower temperatures. In colder climates and in cold rooms (below 70F) they are absolutely necessary. Larger tanks (> 55 gallons) can stand nighttime dips into the 60’s because they lose their heat more slowly, but a 10 gallon tank would need a heater in the same situation for most tropical plants.
I don’t use them in planted aquaria. Plants like fine soil at their
roots and UGF’s will pull the fine clay below the filter
plate. I remember someone once saying,
undergravel filters grow
beautiful roots and poor plants. The roots love to be
able to respire, but many nutrient ions will be oxidized to unavailable
forms with all that well-oxygenated water flowing
through the substrate, and the plants will suffer. Having said that, I
should mention that some people claim success with
Don’t use them. Any fresh air contacting the water will deplete the CO2 dissolved in the water to very low levels. The Aqua-Clear back filters I use don’t introduce enough turbulence to cause major losses as long as the tank is well filled. The plants produce enough oxygen to last all night even for most tightly sealed aquaria. However, if your fish are gasping at the surface in the morning (I’ve never seen this) then turn on an airstone ONLY AT NIGHT when the plants don’t use CO2. You probably have too many fish to keep thinks in balance if this is a problem.
These are not necessary, but if you already have one you can use it for additional water circulation in a 55 gallon or larger tank. Don’t use it with an undergravel filter (since you shouldn’t be using one anyway).
This is one of the most important items to consider for healthy plant growth. I have gotten absolutely superior growth (after having tried many other substrates with much less success) from the following formula. There are two layers:
For the bottom layer mix potting vermiculite (from any nursery) with enough water to wet the vermiculite well but not so much that it’s in a pool of water. Squeeze and knead the vermiculite to get as much air out of it as possible, and also to separate the different layers of the vermiculite granules, making the mixture as fine as possible. When your hands look like they’re covered in gold dust, you’re done. Now add some soil that you have dug from outside (garden topsoil). See the suggestions for soils at the end of this section. You should mix in enough of this to turn the vermiculite from its shimmery golden color to grey. For example, I used about two gallons of Yolo loam with enough vermiculite to make a 3-inch layer in a 55 gallon tank, or about a quart mixed with enough vermiculite to make a 1.5-inch layer in a 10 gallon tank. The precise amounts are not important. After mixing in the soil, the mixture should no longer be runny with water. If it is, your tank will be quite cloudy when you add the water to fill it, so add more soil and vermiculite until it is no longer runny with water, but comparable to prepared cake mix before you cook it. This bottom layer forms a rich, soft medium for roots to penetrate into and obtain nutrients from. This layer should be as thick as possible, within aesthetic limits.
The top layer is simply sand. You need about a 1 inch or more layer, simply to keep the lower layer from clouding the water. The best is #3 sandblasting grit, which our local gravel yard sells in 100 lb. bags for $10. Any sand that is not from the sea and is not too fine will do. #3 sand is about 2 mm in diameter. Just pour it on top, and level it out. Wash it first if you think it needs it. This layer should be at least 1″ thick, and not more than 2″.
Now you can carefully add the water to the tank. Put down some paper or something flat at the bottom of the tank to keep the soil from being stirred up while you add the water. If you are careful, the water will be crystal clear when you finish. If you stirred up the soil by accident, it will take 2-5 days to clear up, so be patient. A small puff of soil will come up when you uproot a plant, but does not present a problem. After you have planted the plants, you can add a small amount of solid fertilizer to the bottom layer of the substrate (see the fertilizer section).
For those interested in what to look for in a soil that will grow
aquatic plants well, here is additional info. Don’t use
bagged potting soil, peat moss, or compost (They will decay under water
and prevent good root growth. See the recent
article by Diane Walstad in the Sept. 1994 issue of TAG. They offer a
short-term supply of nutrients which will have to
be replenished with solid fertilizer eventually anyway, so you might as
well just use a solid fertilizer from the beginning
and avoid the problems associated with decaying organic matter, such as
hydrogen sulfide formation.) Try to find a soil
low in organic matter and high in fine clay particles. It should not
be sandy soil or very firm, fine clay either, but
somewhere in the middle. Sand has insufficient cation exchange capacity
and is too coarse to contact the roots on their
entire surface area. These are the two most important factors which
influence how well roots can obtain nutrient ions from
the soil. Very fine clay (close to Play-Doh texture) might cloud the
water when you uproot plants in the aquarium. If you
are a student, you might want to go to the university library and look
up the types of soils in your area and their properties
in government soil survey books which usually have maps telling you
where to find the different soils, as well as important
chemical properties. You want a soil that has a high cation exchange
capacity and low organic matter content, and has
metal ions which are present in only moderate quantities (high metal
concentrations occurring in subsoils can be toxic to
plants upon initial immersion; see TAG article referenced above). I
Yolo loam from the UC Davis campus with
great success in my home tanks. It was not chosen specially, but it is
just what was available locally.
Here is the analysis:
|% sand (2mm to 0.05mm)||28.7%|
|% silt (50 microns to 2 microns)||46.4%|
|% clay (< 2 microns)||24.9%|
|% carbonates||(not tested)|
|phosphorus in soil||12.5 ppm|
|Fe as Fe2O3||(not tested)|
|cation exchange capacity||26.5 me/100g|
|% base saturation||81.9|
|% organic carbon||1.38%|
|% organic nitrogen||0.125%|
I have also grown plants successfully in softer water. Buying or treating water is unnecessary in almost all situations.
The importance of CO2 injection cannot be overemphasized for growing beautiful planted aquaria. Sounds complicated? Actually it’s easy and cheap! Aquarium companies sell extremely overpriced CO2 setups costing at least $200 for no frills models. These consist of a high pressure tank of CO2 and a pressure regulator, as well as a reaction chamber where the CO2 is dissolved in the water. The setups on the my aquaria cost about $5 for supplies that will last a year (this includes 2 liters of Coke that you get to drink). Here’s the idea (which is due to Thomas Narten off of internet as far as I know). CO2 dissolves into (and escapes out of) water very quickly, so we need a way to produce bubbles of CO2 and to hold them in contact with a fast flowing stream of water so the CO2 has time to dissolve. CO2 is produced by yeast fermenting sugar into alcohol, so take a 2-liter soda bottle and fill it with lukewarm water to about 2″ from the bottom of where the screw cap would be. Pour the measured water into a bucket and add approximately 2 cups sugar and 1/4 teaspoon baking yeast (e.g. Fleishmann’s brand from the baking section of Safeway). Stir until both are dissolved, especially the yeast which is harder to dissolve than the sugar. Pour this stuff back in the bottle and fill to the point it normally would be filled with soda. Drill a hole in the center of the top of the cap which is just wide enough to tightly fit a piece of aquarium airline tubing into it, and glue the tubing into place with aquarium silicone sealant. Leave the cap off the bottle to dry for a day. Then screw on the cap and put the other end of the air tube into the intake tube of the filter, so that the CO2 will bubble into the filter. The CO2 may start bubbling the next day, or maybe not for up to 3 days. The bubbles get sucked into the pump propeller and some end up in the filter sponge where they slowly dissolve into the water where the plants can use it for photosynthesis.
This mixture usually lasts about a month before you have to mix a new batch (more sugar makes it last longer; more yeast makes it bubble faster but it will run out quickly). Watch for when the bubbles are no longer produced, at which time you’ll have a nasty alcoholic swill left in the bottle which I don’t recommend drinking. Keep the opened yeast packets in the refrigerator in the meantime or the remaining yeast will die. Some people have to worry about the CO2 lowering the pH of the aquarium water, but Davis water is so hard that the pH will hardly fluctuate at all. If your water is soft the watch the pH closely during the first few hours of bubbling, and harden the water if the pH gets near 6. I have gotten readings consistently above the recommended level on my CO2 test kit (Tetra), with no apparent harm to the fish. When using CO2 you must have a cover on the tank and avoid using accessories which mix air into the water (the plants add plenty of oxygen to the water), as the dissolved CO2 levels will fall quickly. Note that the bubbling rate is quite sensitive to the room temperature. If you have tried growing plants for a long time with no luck, you will be amazed at the incredible growth that results.
Plants need nutrients to grow. CO2 is the most important
of these, but the others must be added also. If you feed your
fish a lot, then this may supply all of what the plants need. Some
people have beautiful plant tanks with no fertilizer other
than digested fish food. The unfortunate thing about fertilizing this
way is that all these nutrients are available to the algae
as well. If all this digested food could be kept deep in the substrate,
the plants would have a much easier time getting at
it than the algae. For this reason I prefer to feed my fish VERY
sparingly and to use a solid fertilizer in the substrate. I
Lilipons brand pond lily tablets with great success (after
having tried many made-for-aquarium additives which
weren’t as good and are generally overpriced). I break the rather large
tablets into 8 or 16 smaller pieces (best accomplished
by placing a flat-head screwdriver onto the tablet and striking with a
hammer) and push them deep into the loam/vermiculite
part of the substrate. This helps keep the nutrients out of the water
and near the roots. I would use no more than one whole
tablet per 20 gallons water when you first plant the tank, and then add
some weekly until the nitrate levels in the tank rise
above 5 ppm (see algae and test kit sections). At this point there is
probably quite a supply of fertilizer down there and you
can stop adding it for awhile. Note that I assume you are feeding
sparingly enough so that the food alone would not cause
any readable nitrate levels.
Plants also require plenty of iron. The
Lilipons tablets contain
iron, but from my experience it is not sufficiently
available. I have been occasionally adding aquarium trace element
additives (they contain chelated iron and some other
important micronutrients which are usually supplied in tap water, and are
somewhat overpriced) or garden supply iron (any
iron-plus-chelate compound with no other additives will satisfy the
plants, but may slightly discolor the water if part of it
is unchelated). My paranoia stems from a tank I had set up with only a
coarse substrate (no Yolo loam) into which I had
put some of the lily tablets. Plant growth really took off for about 3
weeks after the fertilizer tablets were added, but
suddenly all the plants began dying. When about 3/4 of the plants were
looking pretty sad, I began adding iron daily and
all the plants that hadn’t completely died put out new shoots and came
back nicely. Presumably the roots could not contact
the iron in the tablets well enough to absorb it without the fine loam,
or there was too much water circulation through the
By the way, even tap water contains soluble iron, but in the high oxygen environment of your aquarium it quickly turns to rust which the plants cannot use. Chelated iron doesn’t oxidize quickly and so will remain available for weeks. Also try the Osmocote tablets described below, which are in all respects identical to the pond lily tablets. In summary, I would add some solid nitrogen containing fertilizer in the substrate (especially Lilipons or similar initially at 5 grams per 10 gallons), check for high nitrates (if they’re high (above 10 ppm), stop fertilizing with nitrogen and increase water changes until they lower), and add chelated iron (especially if the plants take a turn for the worse). Note that the proper levels of fertilizer will depend on fish load, water chemistry, and water change frequency, so you will have to watch for the needs of the tank.
For comparison with other fertilizers, here are the Lilipons ingredients:
|20%||nitrogen (7% soluble, 13% insoluble)|
Derived from: urea formaldehyde, calcium phosphates, potassium sulfate, calcium sulfate, ferrous sulfate.
An equivalent tablet is available from:
Van Ness Water Gardens
2460 North Euclid Ave
Upland, CA 91784-1199
A tablet with the EXACT same ingredients and proportions was available
in the tree fertilizer section of our local hardware
store. It’s called
Osmocote (Agriform) Planting Tablets and are larger
than the Lilipons for $0.35 per tablet. This seems
like a more convenient source, since Osmocote is a big company so these
should be available.
(Note: The addition of phosphates and sulfates to the aquarium is not above controversy. I have used these tablets in tanks with NO visible algae growth and without any apparent harm to roots from hydrogen sulfide gas. All I can say is that it works, despite the theory, and new information suggests that nitrogen helps counteract H2S toxicity. These tanks have been set up less than one year.)
I would buy a nitrate test kit (low level), and the nitrates should always register zero or below 5 ppm on the test kit. If they go above 10 ppm then you’re feeding or fertilizing too much with nitrogen, and you should increase water changes and decrease feeding and eliminate nitrogen fertilization until they return below 5 ppm. Be sure you push the fertilizer tablets all the way into the bottom soil so they don’t leak into the water. A pH test kit is useless in Davis, it will always read high, but you will want one if you have soft water for when you start adding CO2. Keep the pH above 6. An iron test kit is nice to check the iron levels but they’re hard to find and often overpriced, and they won’t tell you anything about iron levels in the substrate. No other test kits are needed, but some are nice to have to satisfy your curiosity.
It is natural to be apprehensive about where and how to position the plants. Look at the book Nature Aquarium World by Takashi Amano for artistic inspiration. Then just go ahead and do it, and remember that it won’t look good until the plants grow in, so wait a month or two before repositioning anything. Most plants don’t like to moved too often. One rule that you should follow is to plant very densely. Remember that plants use up available nutrients from the water and thereby prevent algae from getting a strong hold. If you try to save money by planting one plant at a time, you’ll only grow an algae garden. Excess space can be filled in with cheap fast growing plants like Ludwigia, which will quickly use up excess nitrates and/or other nutrients, and can be partially or completely replaced later with fresh cuttings of more other plants. As a fast growing stem plant reaches the top of the water, you’ll want to cut off the top 1/2 to 2/3 of it and replant it, leaving the rooted bottom to produce new sideshoots. In this way a small amount of a stem plant (even one cutting!) can be turned into a thick garden. Rosette plants with roots should be pushed too far into the sand first, then pulled up so that the point where the leaves join the rootstock is above the sand. Small plants can be held down with pieces of bent wire until they root.
Among people who can actually grow plants, algae is the main headache. The main rules for algae are don’t panic and don’t use any algicides. Algicides will kill the plants too and algae can be handled by addressing its causes and being patient enough to try the solutions. One main cause of algae seems to be unhealthy plants. I have used cuttings from algae-plagued tanks when setting up new tanks according to the above suggestions, and have been able to completely eliminate the algae once the plants grew in. It seems that the worst kinds of algae, filamentous algae and red algae, can thrive even in water that is starved of nutrients when they are attached to a dying leaf (I don’t know if it derives nutrients from the leaf or what). By having only healthy leaves in the tank, you have already eliminated the favorite breeding ground for these algae. Presuming you are starting with no-so-healthy cuttings from an unsuccessful tank, so that most of the leaves have firmly attatched algae, you must grow out new leaves as quickly as possible so you can eliminate the dying leaves. This is the job of the suggestions presented above. In the mean time, cut off any leaves that are badly covered, and as soon as a stem grows tall, cut it off at the point where the algae starts and replant the top, and discard the bottom. For rosette plants just cut off the infested leaves when sufficient new ones have grown. For me this has been sufficient to eliminate all algae problems (to the point of no visible algae) when I followed the setup techniques outlined above in some of my tanks. However, this does not eliminate the chance that variations in your tap water chemistry and fish feeding habits will make your job more difficult.
If the above suggestions alone worked always, many plant keepers would be much happier. The truth is that you can have very healthy plants AND algae at the same time, possibly due to excess nutrients in the water and (less possibly) excess light. The truth of the matter is that no one I know of has a firm handle on what can reliably be done to limit algae growth in all cases. Many aquarists have similar tanks side by side, only some of which are plagued by algae, and others of which are spotless. If you have a problem, test for nitrates. If they’re above 10 ppm then add more fast-growing stem plants which will help to quickly use nitrates, and decrease feeding and stop adding nitrogen fertilizer. If nitrates read zero, there may be too much light and you can SLOWLY lower the light levels by putting toilet paper or equivalent between the lights and the top glass, while continually removing algae and watching how fast it grows back. More likely to cause algae than either excess nitrates or light are excess phosphates originating from fish food or decaying plant leaves. At present the only known ways to remove it are with a phosphate removing resin (Phos-Sorb for example) or by water changes.
There is one type of algae that may thrive despite all this advice:
blue-green algae. This algae is actually related to
bacteria and will respond to treatment with erythromycin, available at
most pet shops. Follow the instructions indicated
for bacterial infection of fish on the label, but use only half the
dosage. The people at the pet shop will think you’re crazy
for using it on an
algae, but remember that the pet shops are poor
sources of information and that blue-green algae is
actually a photosynthetic bacteria. I have used the brand
with success and it has never reappeared. This algae
can be identified by the color (usually more bluish than most algae) and
the fact that it quickly coats plants/sand in a thin
layer like a veil, which is easy to remove from the plant but grows back
very quickly. It is not stringy or tufty. This
treatment will not harm the filter bacteria if the directions are
followed (using 1/2 strength). Some people even claim that
a single day’s treatment will eliminate blue-green algae, so use as
little as possible. If you’re not sure, get an expert
identification before using the medication. Many snails are said to love
to eat blue green algae (e.g. ramshorn and pond
snails) and thus provide an organic (but not as quick) remedy.
O.K., that may sound like a lot of requirements, so what is the bare minimum low budget setup? You need at least a full spectrum fluorescent light for the hood you already have, the CO2 generator, a filter for circulation and CO2 injection, the sand/vermiculite/soil combo I suggested, an Osmocote planting tablet or two, and a nitrate test kit. This all should cost about $40 for a smaller tank. The best improvement on this bare minimum would be to add more light. With any luck, another TAG article will follow which summarizes some soil science principles and soil-plant relationships. Until then, I hope there is valuable information for you (or a budget-minded beginner) contained above.