The single most annoying problem in your aquarium is likely the ongoing battle against algae. Left unchecked, it can cover the glass - in colors ranging from black to bright green - making viewing your beautiful inhabitants impossible. It can also quickly cover the decorations, diminishing the appeal of the entire environment.
Some algae is easy to remove. All you need to do is scrub. To help keep water clean, use of a premium grade carbon will help reduce dissolved organics and slow the return of algae. However, if certain types of hair algae appear in your aquarium you may have a persistent problem that requires tougher measures.
Many aquarists who encounter hair or other tough algae treat the symptoms, not the problem. For example, they may bleach all their decorations and gravel and then treat the water with a dechlorinator, placing the health of their fish at risk, only to discover the algae making a fast comeback within days.
If you want to avoid algae problems, it is a good practice to test your tap water before changes. Likewise, if you already have an algae problem, your first step should be to test your tap water. If the test results show significant levels of phosphates or other algae inducing elements, your battle against algae will be futile until they are reduced.
Most phosphate comes from three sources: tap water, fish food, and carbon. In the case of city water, the municipality may actually be adding it to protect its pipes. In well water, phosphate often come from the leaching of lawn and garden fertilizers.
To avoid unwanted phosphate levels, make sure no uneaten food is allowed to remain in the aquarium. To reduce or eliminate phosphate already present, commercial phosphate removers can be effective. Of course, an excellent way to start is by using water purified through reverse osmosis (RO), and then using it for regular water changes.
The right choice of filter media can also make a big difference in phosphate levels:
Poly Filters will remove phosphate and heavy metals, and actually provide an indication of existing problems by changing color. Blue for copper. Orange for iron. Green for ammonia. Dark brown or grey when exhausted.
Combination Carbon-Phosphate Remover products are also available. These products not only neutralize any minute amount of phosphate released by the carbon, but also remove it at large in the aquarium. The carbon keeps your water crystal clear and removes dissolved organics, the phosphate disappears, and, best of all, so does the algae.