How do ferts help control algae?

[ahelmes71]

This may be a dumb question, but I've seen some people recommend dosing with Flourish or products like that for helping with algae.

Why would the fertilizer make algae go away? Wouldn't it just encourage algae growth along with the plants? It seems counter-intuitive...what am I missing here?

Andy

 

[Mumma.of.two]

It helps the plants out compete the algae. Algae takes over when the conditions in the tanks aren't ideal for plants. When everything's in balance and the plants are growing well they out compete the algae.

 

[aqua_chem]

One of algaes advantages over plants is that it is actually collections of thousands of independent organisms, while plants are collective organisms, living and dying as one. This means that algae can survive with smaller nutrient levels than plants can. Plants, however, are a must more robust organism, allowing it to beat out algae of properly supplied.


Lets pretend for a moment that things are simple and can b easily expressed in an analogy, shall we.

Imagine algae as a group if bandits: loosely organized, scrappy, and completely self-serving. Plants on the other hand are like an army: large, powerful, but resource intensive. If the army is well suppled with grub and provisions (ferts and co2), the army would easily crush a group of bandits. If, however, they are lacking any one supply (ferts or co2), the bandits will be terrorizing the countryside (your tank) with the 'army' ill-equipped to handle them.

Its a simplistic metaphor, but I hope it makes sense.

 

[ahelmes71]

The best metaphors ARE simple, Aqua Chem, and I understand your drift.

So when the plants are up and running at full steam ahead, I take it they will utilize all available resources in the tank, but when they aren't doing so good, the algae steps in and opportunistically thrives on available resources.

 

[aqua_chem]

Exactly. This is why the concept of balance is so important to planted tanks. Any excess of a resource, whether it be light or nutrients, allows the opportunists to come in and muck up your tank.