The daylengths are now 16 hours. There has been a massive algal growth this spring. The new, heavier feeding regime has had an effect on the nutrient input. But most important, the added heavy flow from the 65 Watts pumps have probably contributed to much more algal growth. A lot of Ulva bloomed, and reached fairly good size too. Even my old friend, the red sea lettuce (Porphyra) came back. The Ulva bloom seems to be mostly over now. But new Porphyra pops up here and there.
New rocks are important in algae tanks. I collected a seemingly fairly barren rock late last year. I don't even remember the reason I collected it, maybe some hydroids. Anyway, this spring it suddenly bloomed with about a dozen fresh kelp speciemens of two different species Laminaria saccharina and Alaria esculenta. This rock's population is now becoming a major contributor to the algal mass, and it is situated perfectly in the middle of the tank right in the stream from the pumps.
I don't know what species this is. I can't find it in my algae handbook. It just came up this spring and was looking really nice. A few days after the picture was taken it let go of the sustrate unfortunately.
I've had some great collection trips lately. The sea is full of plankton. It is so extreme that some places the tidal zone smells strongly of dead plakton at low tide. Small tidal ponds turn into cesspools of dead copepods. At one spot I found hundreds of gorgeous nudibranchs. They were orange and white. Unfortunately they feed on some hydroids that I just don't have enough of. So I couldn't take them. The coolest things I've found lately were two pink-purple starfish (Henricia sp.). I really hope they will do well. I think they may, because they were supposed to be oportunistic scavengers. Other starfish have done very well in the tank too. I'll see if I can get some pictures of them in the next update.
I have done some more observations with the plankton project. The cultures seem to grow to a certain, fairly low concentration, and then stabilize like that. As time goes, more and more benthic alge will grow on the plastic. It is nice to see that algae will grow into concentrations directly from seawater. But indications of the challenges with growing phytoplankton in a refugium show up. Algae attached to the walls will have a competitive andvantage over the phytoplankton since they are not washed out. There may be algae eating organisms that limit growth. I wanted to test the concentration of nutrients in the reactors at various times. But I don't have a filter that can filter out the bio material in the water. And then I suppose the biomatter will affect the test is some way. So I didn't try measuring that. But I did a test were, after splitting the cultures, I added much nutrients in one bottle and little in the other. The one with much nutrients got greener, but not very green like a monoalgal culture.
These cultures have been left to grow for about 4 weeks without observed increase in concentration. The one on the right had 15 ml of extra flower fertilizer added to it compared to the 5 of the one to the left. The concentration of algae doesn't seem to be higher in any of them. But the growth is obviously different. Notice how the benthic algae have settled on the plastic and have been gradually expanding.
I really love my ozone. It is one of the best things that has happened to my tank. It is extremely important for water clarity. Without it I would have to feed very little, and even then the water would be unclear. It is almost essential for an algae tank like mine. But it is certainly dangerous. I just read a forum thread about a guy who worked in his stand cabinet for a few minutes with the ozone hose disconnected. He breathed ozone gas and got very ill. He had to be rushed to the hospital with ambulance, and his throat and lungs stayed sore for weeks.
The trouble with ozone is that it erodes certain types of plastic. There are good charts showing which types of plastic it erodes. But that doesn't help when it nevers says on small air T connectors and air wents which plastic they are made from. My T connector eroded into nothing, only a thin crisp shell was left. Then it broke off. For a day or two the ozone generator ran free. For some reason I never smelled any ozone. Not even in the cabinet. That may be because I have no air pump connected to the ozonizer. So there was no air flowing through it once it was disconnected. I use a bypass system where the skimmmer sucks air in through a T connector where one end is connected to the ozone generator. I highly recommend this setup. An air pump to the ozone generator is a risk. The hoses also had started to melt on the inside. Now I have silicone hose and a new T connector. But I still don't know if it is the right type. I'll watch it carefully this time.
Finally I am seeing some of my chameleon shrimps surviving over time. I've added these small, 2cm long, shrimps to the tank all the time. But they have always disappeared after a short while. But now I see indications that they stay for more that a few days. Whenever I look carefully at large algae I can see chameleon shrimps hiding. The one on the picture is a female with eggs, sitting on a branch of Sargassum muticum cleaning herself. They change colors after the environment and can have colors like brown, green, red, pink, purple or combinations of those.
I am now seeing some more signs of clams feeding. For example, most of my remaining mussels (Mytilus edulis), are open and feeding most of the time. Not quite as wide open as in nature, but nevertheless. I also have some other mussels (Modiolus modiolus) that are feeding. Some scallops are hanging in there, and seeming to feed well. I have had scallop losses this winter though, and I haven't observed any growth.