The Puffer Forum

A circulating system will equilibrate at the mean value of the salt addition. Basic chemistry. You cannot defeat chemistry.

Even if you segregate the SW/BW/FW by semipermeable membranes, water will still move by the natural osmotic gradients to dilute the BW and SW, which will overflow while the FW empties itself into the others.

If not only is not nice to fool Mother Nature, it is impossible.

The analogy of FW flowing int BW and that into SW cannot hold in a closed system unless it is planet-sized and you have evaporation from the SW to replenish the FW as rain/snow/sleet.

zooplankton is just a generic name for organisms of a specific size.

RTR already suggested this - rotifers.

rotifers ae relatively easy to culture - but you nee dto first get a culture of green water (phytoplankton) going to feed the rotifers.

And be super-cautious not to contaminate your green water cultures with the rotifers - do not ask how I know this...

That's pretty much what I figured RTR, and I know we've talked about it before.

The only thing I could think of was to use gravity, but it would have to be a constant flow of new freshwater all the way down into a very large saltwater tub, which would then need to be partially drained and refilled constantly.. There's a chance it could be done (auto water changer type setups), but wow, what a huge system and a load of work!

ooooh! I know! To make it a self maintaining system of sorts....you have a desalinator down at the salt water end, and have the fresh desalinated water pumped BACK up to the fresh water end.

would that work???

>.>

Nope, because then you'd be constantly taking salt out of the system.

Have to have it all balanced out to add back the salt that's being removed, so it would likely have to be all computerized and everything. Levels being monitored, proper amounts put back in... Its something *maybe* a large aquarium might be able to do but I don't think it could be done on the home hobbiest scale.

surely a reverse osmosis system at the end the output of which is then pumped back up to the top would work, if extremely impractical on the scale required (and the freshwater part would be ridiculously soft)

again, you'd be removing salt from the system that way

sorry i just read the last couple of posts and saw that had already been suggested...

you could have water from the saltwater section gradually removed and desalinated in a separate unit, with some of the water removed as fresh and returned to the top of the system, with the salty solution that remains injected into the system in various quantities down the system flow to increase the salinity to brackish in increments? obviously this would have to be finely computer controlled as previously mentioned, and would take up loads of space. i imagine the downhill current would be too strong too.

From what I can recall from my time in the Navy, the efflux of a reverse osmosis system is usually rather toxic, and needs a large amount of filtering before being returned to the environment. However, that wasn't my "part-ship" so I'm not exactly sure what was so toxic. However, if that wasn't a problem you could use a ROD to remove salt from the water and have 3 outputs, one fresh, one brackish and one marine, the majority being fresh. That way salt could be returned into the system. This would have to be extremely automated though.

The technology to have and manage that is simply not available.

Setting a complex ecolgy in a single water type, as Adey et al have done is quite hard enough. Setting from rainwater to the sea is a pipe dream.

I'm not sure if Touchmaster Odd already suggested this. Could you have two large vats one containing fresh and one containing salt water either end of a long and reasonably deep 'river' construction, with water being set to trickle down into either end, one side receiving salty water and the other fresh and in the middle where the water would be mixed a certain amount would be allowed to trickle down and out of the system continuously being replaced by the made up solutions in the vats. If the flow was properly regulated would this simulate a river flowing into an estuary?

im not saying the technology is available off the shelf in any way or that it wouldnt be incredibly expensive, im just saying that given unlimited cash and the inclination surely it would be technically possible

Instead of just dreaming and guessing, why not do a little research?

A web place to start is:

http://www.angelfire.com/ri/skibizniz/mcosmlinks.html