[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Cable flow rates/Bacteria



>> Roger Miller wrote:
>> *If* the cables cause circulation then it's possible.  I'm not entirely
>> convince that they do cause convective circulation, but then I don't
>> think that they have to cause circulation to be useful.
>> 
>> For every drop of water that circulates into the substrate there's
>> another one that circulates out.  The circulation rate is low
>> (presumably, anyway -- I don't know that anyone has ever measured it) so
>> you wouldn't expect a big effect.

Claus of Tropica mentioned that they tested one tank for optimum flow rates
in the substrate and came out with a figure of .49 liters/m^2/day. Not much.
Osmosis ain't far behind that. But that was one tank. There are so many
issues dealing with the flows of cables it is IMO too difficult to get
formal data for it in the long term use. I think the bacterial action of the
warmth produced is the biggest contributor hence my suggestions of a reptile
pad. This is why I believe the RFUG's that I used for many years grew the
plants very well too. A healthy colony of bacteria will support a healthy
plant population and cycle the nutrients well. A deep gravel bed will be
much better than a shallow gravel bed etc etc. All functions of bacteria
colonization.

Deep Gravel
Warmth
Some flow through(RFUG's (CPVC) etc more aerobes)
High surface area of Turface-flourite etc.

I divide these into 3 categories based on flow:

-------------------------------------------------
No flow: Osmosis-flourite, turface & soil etc
Low flow: Heater cables, heat sources
High flow: Reverse flow UG's, regular UG's etc.
-------------------------------------------------

They all have amplified bacterial colonies in some way. The bacteria don't
live that long either. The death of a few bacteria can be used as food by
the plant's roots and by the other bacteria. Each method has it's trade
offs.
No flow can be slightly less stable when redoing your tank heavy pruning
etc. This makes sense since it will take longer to recover than the other
two methods. But it is simple/works well to keep the good stuff into the
substrate.
Heat methods can cost and can be cheap as well. It is close to the No flow
regarding the redoing of the tank but not quite as bad IMO. A good surface
vaccumming and water change after takes care that problem.

RFUG's are extremely easy to redo a tank with and have no crashing. This
makes since since most of the gravel is aerobic but forms pockets of
reductive zones below the outputs in an egg carton design(Tunze approached
this idea many moons ago which I saw a few years later). There's less area
of reductive zones and they are all on the very bottom. The tank with a RFUG
tends to need more water column dosing than the other two. It's a leaner run
tank concerning the substrate but gives more flexibility with the water
column and provides a higher fish capacity for the tank since there's more
of the filtering aerobic bacteria. But the bacteria are next to the plant's
roots in this case instead of the filter box. An emmersed plant filter does
the same thing here. I have not been too keen on regular plate style UG's.
The CPVC grids are better suited and cheaper and are great for RFUG. If
youre going to try the UG method I would highly suggest that you use this
method over plates. Roots don't get tangled up, some areas of reduction are
still present etc. My flow rates were quite high(75gallons/sqft/hour) but
dropped off to about 50G/sqft/hour after a few weeks.

Deep gravel beds always have done better than the shallow ones for me and
most everyone's tank I've ever seen. All three methods stand to gain from
this addition. Warmth as well if you want to drive your tank "faster".
higher surface areas etc.

I like the no flow the best of three. Nothing extra to buy, plug in, hook up
etc. All the methods work. I'll pick the easy less unsightly cheap one.
I haven't tried cables with flourite. Is anyone doing this? I did as reptile
pad but it got to hot this summer to keep it on for any length of time and I
got distracted and lost interest.
The pad did as well the Cable set up I did on a 20 gallon tank with sand
laterite mix. I can't say they are much different myself in the real world.
Regards, 
Tom Barr