Spirogyra - Silk Algae, Water Silk

This non-branching green filamentous algae is called Spirogyra. This algae doesn't appear in polluted water systems but in ones that are eutrophic, rich in nutrients (liquid ferts, CO2 and light).
It grows very fast, forming long, entangled strands. I would personally call this one the "spaghetti algae" :-) , the way it looks to me. I am not sure algae eaters will eat Spirogyra. This aquarium of mine has Otocinclus and Neritina Zebra snail, and they are not showing any interest in eating it.
I have removed this algae manually, very easy really.

Since the beginning of this set-up I have used the Estimative Index fertilising regime, dosing 2-3 times a week N,P,K, traces and liquid Carbon (Easy Carbo), so I don't think any nutrients were missing.
There is one problem I have caused (I assume). Instead of performing 50% weekly water change I did 25% every 2nd or 3rd week. I wouldn't say that irregular water change induced this algae but dirty filter (I clean filters with each water change). The filter gets dirty and reduces the water circulation. Less circulation = slower nutrient transport. Also weaker surface agitation = less Oxygen.
I did some tests by doing water change every 3-4 weeks but cleaned the filter every week to keep good flow and moderate surface agitation and this algae never came back.
So keep your filters clean ;-)

Photos by Dusko Bojic.