Algae

Algae


Growing most algae species on purpose is a very difficult task. Many tried many failed. So why is it growing when we don’t want it. There are theories why, unfortunately no agreement yet. From years of experience aquarists know that in the long run killing algae doesn’t work. It comes back. What works in most cases is to keep plants healthy and algae will disappear.


FAQ


Can phosphorus removing products kill algae?

No phosphorus P no plants.


Both, plants and algae need phosphorus. If it is removed, algae may slow down but plants will die. Dying plants start leaking nutrients which algae will use to grow.


When phosphorus is available, algae may start growing and plants will grow healthy. Healthy plants will resist algae and release chemical warfare allelochemicals that will kill algae around them.


Judging the situation without a PO4 test kit is impossible. The actual water column concentration is needed in order to determine if the problem is too little or too much of PO4. Both is bad. If PO4 is on the lower side of the test kit scale then it needs to be added. If it is on the higher side of the scale then more plants or less fish is needed, or existing plants are not having enough other essential nutrients.


Can we starve algae by limiting nutrients?

First we need to understand that algae can not be starved to death. The theory about nutrient competition between algae and plants is false. Even if we get demineralized water, water with no nutrients, algae will still grow in it.


Does CO2 kill algae?

No, it does not kill algae. I placed algae in small amount of water in a sealed jar with only CO2 and waited, and waited. The algae never died.


Will blackouts kill algae?

Covering aquarium with blankets for few days may kill some algae. However, the blackout weakened the already fragile plants and did nothing to remove the cause of the algae infestation on the first place. So algae will certainly come back.


Is high PO4 causing algae?

Phosphate PO4 is usually associated with algae because it is found in high levels mostly in poorly maintained aquariums and therefore already infested with algae. PO4 does not cause algae because there are algae free aquariums with elevated PO4 levels.


Is PPS-Classic or PPS-Pro limiting PO4?

No, PPS dosing does not limit PO4 water column levels. We can have any level we want by decreasing or increasing dosage. The point of the fertilizer is to daily compensate for plant uptake while not allowing PO4 buildup.


How do we combat algae then?

We know it can be done because there are algae free aquariums. How is it done? It is done by providing the right conditions for the plants. When plants get what they need to be healthy (See Plant requirements), they suppress algae all the way to the point where algae melt, go dormant or die.


How do plants do it?

There is clear evidence about plants releasing chemicals to negatively alter other plant species. Unfortunately not much research has been done for aquatic plants yet to prove it. Nevertheless, if we look at it from years of experience, plants suffer, die and melt in algae infested aquariums. On the other hand, algae suffer, die and melt in presence of healthy plants. So let’s put science aside and assume this is it… Then, suddenly we know how to steer planted aquarium to success.


What to do with already infested aquarium?

Plants covered by most types of algae can be washed with running tap water. This does not harm the plants as chemicals do. Then plants can be placed back to aquarium to continue growing. However better not to disturb them much.


In case of BBA the infested plant parts can not be repaired. This algae grow into the plant tissue inside. So the best option is not to weaken the plant further by chemicals but get it into a good healthy environment where new leaves can grow so later you can remove the infected portions.


For driftwood, plastics, hoses, rocks, pumps, decorations and so on can be brushed in tap water.

Algae spores are present everywhere and can not be eliminated. What we can do is to create conditions (See Plant requirements) where algae can not grow, in presence of healthy plants.