I am building and testing an algae "scrubber" and thought I'd keep a record.
I think it has been about 12 days since I set up the ATS for my 80 gallon freshwater tank. I harvested one of the 6 pads today and got a good sized pile of mixed algae. Maybe 4 - 6 grams wet. I mixed it with a little top quality fish food, water and agar in a pot on the stove top. It made about 4 days worth of gel food for my goldfish.
I was a bit surprised to see algae growing on the glass again after cleaning it at the start. I was hoping it would not grow there anymore.
am seeing long hairlike algae. this is what i am after; spiro and similar green hair. Most is brown, likely due to photolimit induced die back. a small tuft growing on a low two dimensional grid is pure green. This is exactly what i want. i think the light is lower here but it may also have something to do with bacteria having less substrate on this media versus the pad media or the depth of water and or lower current caused by being recessed lower than the surrounding pads. the bac may have speeded initial growth but then overrun the algae on the pads. score one for 2d plates vs. 3d pads.
if it is due to the lower light the difference is about 1/4 inch further away from the light, so the light is indeed dropping off very drastically in short distances from the bulb as i was advised it would. A very small margin of height adjustment capacity built into the unit would suffice for fine tuning light levels.
I must say that watching tis stuff grow is very interesting. It is very different every day. People who like "pearling" would be surprised. It is often almost completely covered in large O2 bubbles. I may have to be careful about O2 oversaturation. I read that ~110% can kill fish by giving them a stroke via O2 bubbles passing through the gills. Gassing O2 out and CO2 in is my main question right now.
Unfortunately I was hasty and didn't test my nitrates before it was up and growing, but they were always accumulating and are gone now. I will stop and restart with proper testing sooner or later. Let me see about getting some pics...
Toms post gave me a lot to think about. My algae is growing as we'll as expected but I am going back to the drawing board with the design in order to increase production rates . Emergent or floating Plants outperform algae and a plant filter is a better choice for an easy way to export nutrients but algae has certain qualities which make it better suited to certain applications. I will post more when I get to a real keyboard.
So why am I doing this if I know that plants export more nutrients? Because I want a compact filter. I have an excellent design in mind for a plant filter and I will build it someday. It will consume more nutrients than anything else possibly could, but it will be both bulky and complex compared to my algae filter. Macro algae (as opposed to green water) is very good at exporting nutrients but is limited by being stuck to a surface in a thin layer where as plants grow in three dimensions. This is both a weakness and a strength. You would have trouble designing a plant filter as small as my algae filter. My algae filter may not be as powerful as a plant filter, in theory, but it can be engineered to produce close enough to the same export rate to be fully effective and, in reality, can be made smaller than a plant filter. Smaller tech is better tech, IMO.