Stuff you need to know about plants

[SniperY]

Plants are essential if you want to keep a successful aquarium cheaply, and - if all goes according to plan - with very little effort.


Nature's purifiers
Plants take up ammonium, which is toxic to fish. Yet they also protect fish by removing heavy metals such as lead, cadmium, copper and zinc. But they also extract nitrate. Now although levels of up to 50 parts won't have an adverse effect on fish, higher levels are toxic. Besides, algae feed on nitrate, so controlling this pollutant helps counter
algae outbreaks.

One of the best plants to use for water purification, and which is sometimes used in commercial water treatment plants, is the Water hyacinth. Yet most floating plants work as water purifiers.

These include the Giant duckweed and Common hornwort, the latter which also produces a natural algaecide to fight algae. This is a self-preservation measure on the part of the hornwort, for if algae gets a hold, the hornwort would be smothered.

Floating plants have the advantage that they can remove CO2 from the atmosphere without expending much energy. As they replicate with ease and great efficiency, they also strip out nitrate at a rate of knots.

By covering the surface of water, these plants physically cut down the amount of light entering the light. Again, this helps cut down on algae formation - and gives fish shelter.

Most floating plants have long roots that trail downwards. These become colonised with bacteria, acting as biological filters in their own right.


Constant change
The pH of your tank will fluctuate quite dramatically during the course of day and night as a number of processes take place in your tank.

First is the action caused by the friendly bacteria that oxidise waste from fish. Known as the nitrogen cycle, these bacteria first reduce ammonia to nitrite and then nitrate. This process of oxidisation makes the water acid and lowers pH.

However, during photosynthesis, plants will remove CO2 from the water, making the water alkaline and therefore neutralising the effect of decomposition. So plants help stabilise pH.

Photosynthesis also means that plants produce oxygen during the day, which benefits the fish. These chemical process account for fluctuations in pH. As an experiment, test your water in the day with lights on and at night with lights off. You'll see what I mean.

There are two types of bacterial processes: aerobic and anaerobic.

Aerobic processes require oxygen. Such bacteria convert organic matter from fish food, waste and other debris into nutrients that can be easily absorbed by plants.

In soil where oxygen is not present, anaerobic processes produce iron and magnesium. However, you also get that rotten egg smell that is produced by hydrogen sulphide, a gas that is extremely toxic.

Hydrogen sulphide rises through the substrate and as it does, makes contact with thousands of aerobic bacteria which oxidise out the harmful effect of the gas. This bacteria receives the vital oxygen via the action of the plant roots.


Keeping it healthy
So really, the key to a healthy aquarium is good plant growth. Plants need nutrients, and these are obtained from the water, a soil-based substrate, fish waste and fish food. Most of these are provided through your weekly routines, so savings can be made on fertilisers.

For a successful substrate, you need no more than 2.5cm/1" of loam-based substrate - aquatic soil is ideal. Cover this with 5-8cm/2"-3" of fine silver quartz gravel.

Encourage your plants to grow out of the water - they work more efficiently growing in the air, which benefits the whole eco-system.

Don't be surprised when the shape of leaves growing out of water changes. Classic examples are Hygrophila corymbosa and difformis. Under water they struggle to extract CO2 and the feathery leaves of difformis flop around, gathering nutrients with the help of bacteria.

Out of water, the leaves and stems have to stand up to the elements, so the stems harden and the leaves change from the narrow and elliptic to more oval. The best thing is when they produce wonderful purple flowers that will flower for more than four months.

The message is simple - let your plants breathe. Try a small, open-topped tank; you won't be disappointed. When they grow out of the water, the effect is amazing.

Of course, plants need light. Daylight is ideal, and occasional sunshine is of great benefit. Don't overdo it, though, as too much will cause algae problems. If you can't achieve this, any good, cool white light works just as well.

[SniperY]

My plants are covered with unsightly algae. Please help.
In most cases, algae is caused by poor water quality. Various factors could have led to this, including:
1. Overstocking of fish has caused an unhealthy build-up of nitrate and phosphate.
2. Over-filtration has resulted
in increased nitrate and CO2 depletion.
3. Too much stimulation from excess light.
4. Too much feeding, leading
to ammonia, nitrite and nitrate build-up.
5. Cheap, frozen food with algae spores added to the tank.

If you avoid these common mistakes, you are halfway to curing your algae problems. Another cause of algae is, surprisingly, not enough plants.

This need not be expensive as you can fill a tank with cheap, fast-growing plants such as Vallis, Ludwigia and Hygrophila, and cover the surface with floating plants.

As you tank matures, you could replace these with more expensive plants. You must also remember to change the water frequently. At least 20% every two weeks.

There's a calculator on this PFK website to help you determine the correct regime.


I have a terrible problem with snails. What can I do?
Snail problems often occur in tanks that are overfed and poorly maintained. In small quantities, they are not a real problem and do not cause much damage. They help aerate and turn over the substrate, so they may benefit the tank ecosystem.

They do become a problem when they multiply in vast numbers. Unfortunately, most snail treatments are copper-based which can be toxic to the fish, the plants and your filter.

I prefer an organic alternative. You can remove the snails by baiting them with a lettuce leaf tied to a piece of thread. This can be removed the following morning with the snails attached.

Alternatively, siphon them out just before the lights go on. If you do this eight to ten times over a two-week period, you should reduce the snails by about 75%.

Another effective treatment is to have fish that feed on snails, such as loaches. If you do not feed Clown loaches, Botia macracanthus, for a few days, they will hunt out the snails.

The only problem is they are susceptible to white spot and I think they damage plants. Botia striata and Botia rostrata are cheaper and usually cause less damage to plants.


You often refer to the benefits of floating plants for algae control. Can you explain?
Floating plants are one of the easiest methods of controlling algae.

First, they cut down on the light levels, which is especially important in a new set-up when the light tubes are at their most efficient.

Second, they strip out nitrate and phosphate, one of the causes of algae.

Third, they produce roots that are colonised by bacteria and work as biological filters in their own right. Some floating plants, such as Hornwort, may produce an algicide to protect themselves. These have the added bonus of acting as simple bactericides and are wonderful for letting Angel fry hide, thus reducing losses.

Hardy floating plants to try are Riccia, Hornwort and Amazon Frogbit. An unusual floating plant is the Hygroryza aristata.


How do I maintain a planted tank successfully?
Check that the equipment is working properly daily, that the heater light is on, and check the flow from the filter and the temperature of the water. With experience, you'll notice any problems by the activity, or inactivity, of your fish.

Change the water and service the filters regularly. Clean the reflectors (or cover glass for older tanks) on a monthly basis as light is quickly reduced by the build-up of algae on the surface. Replace fluorescent tubes annually and change some of the tired, larger plants for smaller, healthier plants.

It is also important to feed your plants. I use a good general fertiliser on a weekly basis, either API's Leafshine or Tropica's Mastergrow.

Once a month, work in handfuls of laterite to the gross feeders - Echinodorus, Crypts, etc. This technique works wonders. For a more sophisticated fertilisation regime, you can use the Dennerle 7, 15 and 30 day system with different nutrients being added, but I find general fertilisers work just as well.

If you have CO2 injection, remember to check the bubble counter and note when the CO2 cylinder was last replaced. It is always good practice to have a spare to hand.

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[el993]

Puffer fish is good snail remover but may not works in your tiger tank cos it is poisonous if your tiger eats it. Usually snail eggs are introduced to your tank when you purchase new plants, remember to rinse them before plant them into your tank, or soap them in very much diluted bleach. Algae happens mainly due to unbalanced water column whereby plants require constant N:P:K and micro nuitrients which should be optimized all the time. Plants start dying because lacks of food (may be due to insufficient light/CO2) and hence algae comes into picture.

[TROY]

Heard that some snails are helping to get rid of those algae though if tank very clean they will start to eat the leaf of your plants. Is this true?