Re: Aquatic Plants Digest V2 #285

In APD V2 #285, Alan Van Neval was asking about the length of break-in
period for a new tank.

All tanks, regardless of size, require time to settle down and function
properly. The amount of time required for a particular tank to reach
this stable equilibrium will vary, depending upon a number of factors -
but is directly tied to the nutrient load in the tank and the presence
of a sufficient number of bacteria to process those nutrients. Alan
complains about a succession of algae blooms in the tank. This is
perfectly normal, different species of algae (and bacteria as well for
that matter) will be successeful at different times in any environment,
depending solely upon the existing conditions in the tank.

Alan did not give any details about the amount and/or type of filtration
in his tank, nor did he report on the water quality (i.e. nutrient level
and load). It has been my experience that the surest route to a stable
tank environment is to start with the purest water available and that
does not generally come out of the tap in an urban area (not around here
at any rate). 

Urban (and a lot of rural) tap water sources are often contaminated with
high levels of phosphates and nitrates, both of which are readily used
by algae as nutrients. Just because water is good enough for us to drink
doesn't mean that it is good for use in an aquarium. If you want to
prevent the algae from exploding over everything, you must limit what
they need for growth. This is most easily done by starting with water
which have VERY low levels of these nutrients AND by limiting the amount
of nutrients you are introducing into the tank until the bacteria within
the tank and the biological filter have a chance to build up a
sufficient biomass to cope with any excess. 

Cutting back on the light level is not necessarily a good thing,
especially in a planted tank. Rooted plants require a certain minimum
amount of light in order to carry out photosynthesis. Algae however,
come in a bewildering number of types which can thrive at very low light
levels. If conditions are not optimal in the tank the algae (and
unwanted cyanobacteria) can out compete the desirable plants for the
available nutrients.

Kick-starting the biological filter, either by innoculation from
another, already stable tank or using a viable commercial bacteria
culture, will also help shorten the time required for a tank to cycle
and settle into a stable equilibrium. So will minimizing the initial
bioload by introducting only a few fish during the first few weeks and
by gradualy increasing the fish load over a period of months, as the
tank's capacity to deal with the wastes produced by the fish increases.

Patience is the single most important virtue of any successeful

So, Alan, my advice would be to test your water for phosphate and
nitrate and if those nutrients are high, start doing water changes with
water which is low in phosphate and nitrate. Low is a relative term here
- consult the FAQ's. Distilled or RO water might be required, if your
tap water supply has an excess of these materials.

Good luck.

James Purchase