DIATOMS PART-1
Introduction to Brown Algae
How does silicate and silicic acid get in your tank?
Introduction to Brown Algae
Brown algae are not a new occurrence in saltwater aquariums. Many hobbyists have, over time, dealt with outbreaks of them and have had to either remove them by siphoning them out, cleaning the tank's panes, or some other method. Diatoms, or brown algae, appear at some point or another in just about every aquarium and are part of the initial set up problems that everyone goes through. They are not limited in appearance though to the first few weeks a new tank is set up.
After the initial stages, when the aquarium is cycled, diatoms and brown algae should not reappear. If they do, there is something wrong with the water chemistry. Note that in this article the words diatoms and brown algae are used interchangeably and refer to all forms of such algae, not just the filamentous or patchy ones but also the encrusting varieties.
It should also be noted that diatoms are "usually" brown in color, but not always. Sometimes green dotted forms appear as well. The reasons for the difference in coloration has to do with the type of pigments that the alga contains (the pigment determines the color).
It has been found that diatoms appear because of the presence in the water of silicates and silicic acid. To avoid having brown algae in the tank, all the hobbyist needs to do therefore is remove the silicate and the silicic acid both from the tank's water, and from the raw water used to prepare water for water changes, Kalkwasser, top-offs of evaporated water, and so on.
It is not enough to treat only the aquarium. The raw water (e.g. tap, well, deionized, reverse osmosis) needs to be treated as well. If you do not, silicic acid will get into your tank's water and will, eventually, lead to the appearance of brown algae because the levels of silicate and silicic acid will slowly build up.
Diatoms need to be removed from the tank for several reasons, because they:
-make the aquarium look very unsightly and do so very quickly.
-grow and proliferate quite rapidly.
-overgrow anything they can, including rock and sand as well as glass and acrylic.
-pose a danger to your hard corals.
-may be hard to remove from acrylic panes without scratching it.
-lower the oxygen levels when they die off in the aquarium.
-pollute the water with more silicate which makes more diatoms grow.
-give rise to anaerobic areas if many of them accumulate in one spot.
How does Silicate and Silicic Acid get into your Aquarium
Many water sources contain silicates or silicic acid, or compounds that contain these elements and these compounds eventually break down, adding silicates and silicic acid to your aquarium's water.
In aquariums where sandy or other forms of substrate are used, silicate can leach "out" of these compounds, and enter the tank's water very quickly. It usually only takes a few weeks for this to happen (at the maximum). Often it happens much sooner. The latter is especially the case if silica sand is used as the substrate in the aquarium (this is too often the case,unfortunately). Although less common now than a year or so ago, hobbyists were adding "play sand" to their tanks to build up a substrate. Play sand and so-called Blasting sand are very high in silicate and should be avoided if you wish to keep silicates low.
Reference has been made to removing silicates and silicic acid from the water. This means that you should attempt to keep their levels as low as you can. You will never really be able to remove "all" of these compounds. Recommended safe levels are below 0.5 ppm, or half of one part per million.
These silicate compounds then start building up in your tank's water since nothing is removing them, unless you actually take some measures to prevent them from doing so. When they build up to sufficient levels or concentrations, brown algae start to appear in patches first (often on the glass or acrylic panes of the tank). Mind you the patches can be hard, filamentous, slimy and can take on various other forms, depending on which particular diatom is growing in the tank.
The real dangerous types are the encrusting diatoms. They often populate the base of corals and grow upwards, pushing the polyp away from the skeleton. Receding of the coral then takes place. This is a real bad situation as, if this continues, the corals will recede more and more and will start to disintegrate, get infected, and you will loose the coral altogether.
Many hobbyists are under the impression that using reverse osmosis water or deionized water will solve the problem, and that doing so will remove the silicates and silicic acid from that water. This is, unfortunately, not the case. Such units, even if combined, will remove silicate and silicic acid for a very short period of time only and, then, the silicate and silicic acid will get through the membrane and the resins and will start to build up in the tank.
"This is really not much water when you consider that most hobbyists believe that using reverse osmosis, deionization or a combination of both, gives them water quality of very high purity levels. Obviously this is not so, and that belief is a totally false one". R.O. and D.I. remove silicates and silicic acid for "some" time" only, after which the membrane of the reverse osmosis filter and the resins in the deionizers let the compounds through.
The conclusion to draw from this is that, regardless of how you filter your water, silicates and silicic acid will find their way into your aquarium's water, and you are going to have to take steps to remove it. If you do not, diatoms will appear in your tank.
GO TO PART-2 CONT.
Introduction to Brown Algae
How does silicate and silicic acid get in your tank?
Introduction to Brown Algae
Brown algae are not a new occurrence in saltwater aquariums. Many hobbyists have, over time, dealt with outbreaks of them and have had to either remove them by siphoning them out, cleaning the tank's panes, or some other method. Diatoms, or brown algae, appear at some point or another in just about every aquarium and are part of the initial set up problems that everyone goes through. They are not limited in appearance though to the first few weeks a new tank is set up.
After the initial stages, when the aquarium is cycled, diatoms and brown algae should not reappear. If they do, there is something wrong with the water chemistry. Note that in this article the words diatoms and brown algae are used interchangeably and refer to all forms of such algae, not just the filamentous or patchy ones but also the encrusting varieties.
It should also be noted that diatoms are "usually" brown in color, but not always. Sometimes green dotted forms appear as well. The reasons for the difference in coloration has to do with the type of pigments that the alga contains (the pigment determines the color).
It has been found that diatoms appear because of the presence in the water of silicates and silicic acid. To avoid having brown algae in the tank, all the hobbyist needs to do therefore is remove the silicate and the silicic acid both from the tank's water, and from the raw water used to prepare water for water changes, Kalkwasser, top-offs of evaporated water, and so on.
It is not enough to treat only the aquarium. The raw water (e.g. tap, well, deionized, reverse osmosis) needs to be treated as well. If you do not, silicic acid will get into your tank's water and will, eventually, lead to the appearance of brown algae because the levels of silicate and silicic acid will slowly build up.
Diatoms need to be removed from the tank for several reasons, because they:
-make the aquarium look very unsightly and do so very quickly.
-grow and proliferate quite rapidly.
-overgrow anything they can, including rock and sand as well as glass and acrylic.
-pose a danger to your hard corals.
-may be hard to remove from acrylic panes without scratching it.
-lower the oxygen levels when they die off in the aquarium.
-pollute the water with more silicate which makes more diatoms grow.
-give rise to anaerobic areas if many of them accumulate in one spot.
How does Silicate and Silicic Acid get into your Aquarium
Many water sources contain silicates or silicic acid, or compounds that contain these elements and these compounds eventually break down, adding silicates and silicic acid to your aquarium's water.
In aquariums where sandy or other forms of substrate are used, silicate can leach "out" of these compounds, and enter the tank's water very quickly. It usually only takes a few weeks for this to happen (at the maximum). Often it happens much sooner. The latter is especially the case if silica sand is used as the substrate in the aquarium (this is too often the case,unfortunately). Although less common now than a year or so ago, hobbyists were adding "play sand" to their tanks to build up a substrate. Play sand and so-called Blasting sand are very high in silicate and should be avoided if you wish to keep silicates low.
Reference has been made to removing silicates and silicic acid from the water. This means that you should attempt to keep their levels as low as you can. You will never really be able to remove "all" of these compounds. Recommended safe levels are below 0.5 ppm, or half of one part per million.
These silicate compounds then start building up in your tank's water since nothing is removing them, unless you actually take some measures to prevent them from doing so. When they build up to sufficient levels or concentrations, brown algae start to appear in patches first (often on the glass or acrylic panes of the tank). Mind you the patches can be hard, filamentous, slimy and can take on various other forms, depending on which particular diatom is growing in the tank.
The real dangerous types are the encrusting diatoms. They often populate the base of corals and grow upwards, pushing the polyp away from the skeleton. Receding of the coral then takes place. This is a real bad situation as, if this continues, the corals will recede more and more and will start to disintegrate, get infected, and you will loose the coral altogether.
Many hobbyists are under the impression that using reverse osmosis water or deionized water will solve the problem, and that doing so will remove the silicates and silicic acid from that water. This is, unfortunately, not the case. Such units, even if combined, will remove silicate and silicic acid for a very short period of time only and, then, the silicate and silicic acid will get through the membrane and the resins and will start to build up in the tank.
"This is really not much water when you consider that most hobbyists believe that using reverse osmosis, deionization or a combination of both, gives them water quality of very high purity levels. Obviously this is not so, and that belief is a totally false one". R.O. and D.I. remove silicates and silicic acid for "some" time" only, after which the membrane of the reverse osmosis filter and the resins in the deionizers let the compounds through.
The conclusion to draw from this is that, regardless of how you filter your water, silicates and silicic acid will find their way into your aquarium's water, and you are going to have to take steps to remove it. If you do not, diatoms will appear in your tank.
GO TO PART-2 CONT.