Page 11 - TBAS-Aug-2020

TBAS August 2020 .................... -11-
will build up in the overflow tubes and break the siphon. The outside
chamber has a reservoir built in so in cases of power outage the

siphon won’t be broken. Some pre-filters are drilled into the bottom of
the tank usually in the corner: there is a stand pipe and sometimes a
panel sealed across the corner of an overflow. But, no matter how it is
built they are pre-filters.

The second part is the wet-dry filter. So why do they call it a
wet-dry? The first chamber of the filter is above water making it the
“dry” part. This chamber is usually filled with bio-balls or DLS material.
With the water flowing over the filter medium, instead of through,

there is a large surface area providing continuous oxygen for the
nitrifying bacteria and no dead spaces. Under the dry chamber is the
“wet” chamber usually filled with a heavier medium like lava rock or
bio blocks. This area still gets oxygen because the water is sprinkled

into it. Sometimes there is another chamber that is also “wet” provided
for carbon, Chemipure or for a protein skimmer (another article).
Then comes the reservoir - this is where water is added and the level
is checked. If it is too low, then the pump will suck in air. It makes a

sound that will wake me out of a dead sleep. If it is too full then it will
overflow when the power is turned off. The pump can be a power
head or a water pump attached to a hole in the side. Anything that will
pump the water back into the tank will work. At the top the water goes

in with an angled tube to allow the water to flow across the surface.
This tube can be the source of a few headaches.
When my friend was building my first wet-dry he flooded his
living room twice before he installed a siphon breaker. This is a little

hole drilled at water level that will suck in air if the power is turned off
preventing the reservoir from overflowing. His wife was very happy
when I picked up the wet-dry. Another time, after the tank had been
up for a couple of years the hole became blocked with algae and

overflowed in my living room.

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