Chapter II. The seeds of despair

If you search the internet for tips to help getting rid of a green water algal bloom you will find the advice is to increase the frequency of water changes and improve general tank cleanliness. The idea is that a surplus of nutrients (nitrates and phosphates mainly) are responsible. So I started changing 10 liters every week and continued vacuuming the gravel. By week 14 the green water had gone so I started doing two-weekly changes with weekly gravel vacuuming. My thinking was that three weekly had been insufficient but surely twice weekly would be enough to keep the water quality up. On the 19th  December 2010 (week 22) I took a video of the tank, from that I captured this still.

Looking at it now, it's obviously cyanobacteria growing on the Ellodea. It's not green! At the time I thought it was hair algae. I watched with pleasure as the cyano got established and by week 24 I introduced three Ottocinclus algae eaters. I honestly thought when I released them that they would dive straight into eating the 'hair algae' as I had read on the forums about Ottos clearing a tank of hair algae in a few days. The Ottos wouldn't go near the stuff. Confused I searched the internet and found a few sites that listed all the types of algae commonly found in freshwater tanks with descriptions and photos. It was on one of these sites that I made the fateful discovery, I had blue/green algae aka cyanobacteria. A quick read up about cyano proved troubling. It seemed nothing ate it, and it was notoriously difficult to get rid of. First things first, what to do about the Ottos. It should have been no problem, people feed them all sorts of vegetables. I tried blanched and fresh cucumber, turnip, sweet potato. Nothing seemed to interest them, even the algae on the back wall of the tank that I never cleaned. They hung from the tank walls mainly, sometimes they looked like they were feeding but it wasn't the continuous browsing I had been led to expect. On Monday 17th Jan 2011 (week 25) all three Ottos were found dead. The problem with Ottos is that they can't be bread in captivity. Wild caught fish are always likely to be problematic because they have to withstand being caught and transported. I have read that Ottos are quite sensitive and difficult to keep but I'll never know if the problem was the Ottos or my tank water. Anyway, after a respectful period of mourning it was time to read up about getting rid of cyano, and embark upon a journey to the gates of Hades itself.