Biofilter effect on algae

This page contains examples of how the biofilter is used to control and eradicate algae in the planted tank. The examples presented below are not random or accidental – the effect of the biofilter on emerging or well established algae is predictable every single time. The aquariums can be in different stage – established, newly established, or having been established for many years, CO2-supplemented or not.

The fundamental factor that causes algae in all tanks is the imperfect functioning of the biofilter. For facts about the aquarium biofilter visit the page that links to this page: Aquarum biofilter facts.

All the examples presented below have one thing in common – a properly functioning biofilter. The aquariums were:

1. Properly established by allowing the biofilter to develop correctly.

2. Rendered properly established by addition of properly developed biofilter material -“mulm”. (The mix of microorganisms, their food, and their waste – the “dirt” found on the bottom and inside the filter media).

Example 1: Blue-green algae (BGA)
Treatment: Biofilter material from an existing stable tank was added.

Before: The tank had a severe BGA infestation that would not respond to antibiotics. The plants would not grow (substrate was clogged with fine particle clay).
The BGA growth stopped completely the same day when the treatment was done. In the course of the next 7 days the BGA were intentionally left in the tank. The algae did not grow at all. After Day 7 all BGA was vacuumed out and it never returned.

After: The images below are of the same tank 2.5 to 3 months later. Minimal water changes (10% every 5 days), no manual cleaning of any kind, minimal addition of fertilizers (Mg and Ca to GH=3 with every 10% water change).

Further development: After the pictures were taken the tank was neglected for 3 months – only water top off to compensate for the evaporation. Never a single issue. Plants took over the tank completely.

Example 2: Black Beard Algae (BBA);
Treatment: Placing the infested plants in a tank with a properly established biofilter.

Before: Picture 1 shows the plant on Day 1 after being placed in the tank.
After: Pictures 2 and 3.
BBA disappearance in the course of about 3 weeks. Progression from Day 1 to Day 14 to the completely clean plant.

Further development: Three more plants as well as driftwood were cleaned the same way. All of them were reinfested with BBA after being returned to the original tanks that did not have properly established biofilters.

Example 3: Soft green algae (Spyrogyra)
Treatment: A single addition of mulm.

Before: The video shows a tank with a severe outbreak of Spyrogyra. The algae appeared as a result of increased light, plenty of CO2, and substrate that was clogged with too much waste material.

After: 3.5 weeks after the treatment the everything in the tank was cleared of all algae, film, thin layers of detritus. Substrate, plants, and equipment looked brand new. The change was very sudden – it took about 36 hours.

Further development: In the 3 months following the video the tank was left on its own – only water top offs to compensate for evaporation. It stayed pristinely clean, the plants grew out of the water and out of the sides of the tank. Predictably the plants starved for nutrients but no algae of any kind ever developed.