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Re: Fresh water reef


On Sat, 16 Oct 1999, Ronnie wrote:
 
> Hi Roger,
> 
> > My tanks were arranged vertically, main tank on top, filter tank on
> > bottom.  I dropped a line from the main tank to the filter and siphoned
> > down to the filter through a float valve.
> I've 3 shelves of small 35-litre tanks and what you mentioned sounds
> applicable to me.  Could you elaborate how the siphon works with the
> float valve (without creating a full siphon).

It does create a full siphon, if I know what you mean.  Details will vary
with the exact design of the valve. The float valve sits in the lower tank
at the outlet end of the siphon and regulates the water level in the lower
tank.  It shuts it off completely if the power goes out, the pump that
lifts water from the sump to the top tank is off for a while and the water
level in the lower tank gets too high.

> 
> > sump beside the tank.  I pumped water up from the sump to the main tank
> > using a small "minijet" pump.  A valve on the line from the pump to the
> > main tank regulated the flow rate.  I kept the flow at a trickle.
> During brownouts, wouldn't the return line become a back-siphon?...
> unless there's a check-valve in place and how do you regulate the
> flow?... with a ball-valve of some sort?

The return to the top tank was above the water line.  No back flow
possible.

The closest I ever had to a problem with this setup was when nitrogen gas
built up below the ugf plate and broke the siphon on the outflow from the
lower tank to the sump.  The pump would then empty all the contents of the
sump into the upper tank.  The sump was just a piece of 4" pvc pipe that
stood as high as the lower tank and it didn't hold enough water to cause a
problem.  This did happen every now and then.
  
> > For rapid nutrient consumption and minimal size requirements 
> > it's hard to beat duckweed.
> Please elaborate more on 'rapid nutrient consumption' with duckweed,
> does it absorb more of specific nutrients like Nitrate and Phosphate, or
> a bit of everything?  Presently, I'm using duckweed, Azolla,
> water-lettuce and water-hyacinth to remove possible nutrient excess in
> the water column.

It's used in some municiple treatment plants to reduce nitrogen (most
normally, as ammonia)  it's main advantages are that it grows and spreads
very quickly, it's readily available and it needs no care.  Other floating
plants will probably act similarly.  Some fish will eat duckweed.


Roger Miller