George Harvey

H Warner wrote: ... We cant import talapia into NM (trust me, I've looked into it) and that leaves trout/catfish. Not many people will deal with NM for "pond fish" and the local fisheries only release fish to state/federal owned lakes/streams, etc. Because time is so short and we need something now, I'm looking at koi. Not edible, really, but they get big after a while and are cheap and legal. Once spring hits, we can look at trout fingerlings or something else. duckweed will be grown and fed and I hear rabbits love the stuff also!

Did you look into importing tilapia as aquarium fish? If you are putting them into tanks and there is no way they can escape, this is okay in many or most states.
Koi are an ornamental strain of common carp, which are the most widely farmed food fish, worldwide. They are not usually considered suitable for food in the US, but I am not sure why. I know some people really love carp. I remember, as a child, coming across an angler walking on the bank of a river, who showed off his catch to me and exclaimed, "Them's carp! Them's good eatin'!"
Trout require a lot of food and are dependent on animal protein. I have not raised them, and am putting off trying because of this. They also require cold water.
Catfish, on the other hand, seem to eat just about anything. I have not seen them wild about duckweed, but they do eat it.
Goldfish, koi, and a lot of others eat duckweed as well. In some parts of the world, duckweed is raised for human consumption. I would not raise it for myself to eat in a fishtank.
You might also try azola, which is a little slower growing than duckweed, but seems to persist in cold better. The fish I have very much prefer duckweed, but some species might like it better. I have not tried it yet, but I intend to. It is also used for human consumption, and has a nice scent. Like duckweed, I would raise it in its own tank for myself.
Watercress can be grown in floating rafts, and fish nibble at the roots. If you want to raise watercress for your own food, do it separately, because the fish prevent it from growing fast. A large number of other plants will also put roots into the water, and I expect fish would eat many of them. Mint is one. Celery is another, but I have not yet seen fish eating the roots.

Some time back, I did some research on this subject, and found some answers. People were asking how they could expect a 50% to 80% reduction in their fuel use when their stoves were already 78% efficient - wouldn't that imply an efficiency of 156% to 360%? Two things I did were research on the efficiency ratings given wood stoves by the DOE, and the characteristics of heat passing from the stove and flue into a building, according to system.
The first thing I discovered was that the DOE ratings have nearly nothing whatever to do with the amount of heat available in fuel that is actually put into the building. What they measure is how well the fuel is combusted. If you think about this, it makes sense. You can measure a stove's output, but you cannot measure the flue's, so in rating a stove; there is a lot of variation in efficiency in stoves depending on how they are installed.
The next thing I did was to do a simple comparison of burn systems. One writer said that he was able to measure a 1000 C temperature in the firebox of a rocket mass heater, and a 30 C temperature in the output of his flue. This compared with a 300 C temperature in the output of his older stove, at the top of the chimney.
It sounds like the rocket mass heater extracted the heat from 1000 to 30, for a total of 970 degrees, and the older stove was from 1000 to 300, for a total of 700 degrees, which would make the rocket mass heater about 138% as efficient as the older stove in extracting heat from fuel. This, however, is not the case, because the flue gas from the rocket mass heater is undergoing a phase conversion at 100 C, where the water starts to condense.
I did some work on this and discovered two things. First, any residual water in the rocket mass heater's fuel will boil, reducing heat of the burn, just as it does in any other stove. The difference is that it delivers most of that heat to the thermal mass, making the rocket mass heater potentially more efficient in extracting heat from incompletely dried wood.
The second thing is far more important. When wood burns, the products of combustion are carbon dioxide and water. The water is in the form of very hot steam. In a normal wood-burning system, that steam is lost to the environment without extracting the heat of phase conversion. In a rocket mass heater, however, the heat is captured. This means that hte 138% efficiency mentioned earlier becomes a good deal higher. My recollection is that it was over 180%. This would correspond with a reduction in fuel use of between 45% and 50%. I would point out that it is not necessarily the only efficiency improvement in the rocket mass heater, so greater reductions in fuel use may be explained by other factors.
The rocket mass heater has a fire that burns for a short while and most of the heat produced is captured in the thermal mass. It is only necessary to burn fuel until the thermal mass heats up, at which point the fire can be allowed to go out, and the heat for the house is extracted slowly over the following period of many hours.
A friend and I have been working on improving the efficiency of a rocket mass heater by using more efficient thermal storage. I will write this up on this forum when I have more information to provide. For now, I can confirm that we had a very hot fire, leading into a four inch flue system twenty feet long. The gas coming out ranged from barely warm - I would guess about 60 degrees F, to somewhat warm, possibly 90 degrees F, depending on how the system was configured. There was a substantial amount of condensation in the flue, and since it ended with a slight rise in the pipe, it had to be emptied frequently between burns, a fact that will need to be addressed as we develop the system. I mention our experiments because they confirm the efficiency gain of the rocket mass heater, and also indicate greater efficiency may be available.
The bottom line here is that regardless of how well older stoves are constructed, they are nearly never installed in such a way that as much as half the available energy of combustion is delivered to the building. The advantage of the rocket mass heater is the huge increase in the efficiency of capturing and storing the available heat.