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**TheRock** · November 21st 06, 02:18 AM posted to rec.aquaria.marine.reefs

/The Conscientious Marine Aquarist

Frequent Partial Water Changes

Probably the most important aspect of maintenance a keeper of an aquatic
system can do to optimize water quality and health of their charges is to
change some of the water is a regular basis. This Section deals with the
reasons for, and some rules of thumb as to how often, how much and how to
make these changes.
Rationale:
There are several major benefits of frequent partial water changes: Dilution
of nutrient, removal of particulate matter, reduction in microbial
populations and their metabolites. Results anticipated are faster, more
vigorous growth, reduced algae growth, color and odor.
It has been written in many fisheries, limnological and hobbyist texts that
along with temperature and photoperiod, metabolite ("wastes") build-up is
one of the three most important factors influencing the health, growth and
reproduction of livestock.
More specifically; in the trade, ammonia and other nitrogenous wastes are
recognized as the number one killer of aquatic life in captive conditions.
Not to say that all the "stuff" produced by the system's desiraable life is
toxic. Some metabolites, like pheromones, are actually known to have calming
effects. Therefore the concept of partial, not total water changes.
In doing these water changes we are interested in a dilution-solution; that
is, keeping these so-called waste products at tolerable levels.
There are several ways this is otherwise accomplished. Most common are some
forms of biological filtration and chemical filtration like carbon and
ion-exchange materials. The last are useful but often labor and money
intensive. Moreover, these chemical filtrants do remove desirable chemicals
as well.
As stated in so many previous Sections it is imperative vital that as much
extraneous materials: foods, dirt from decor, material from the immediate
outside environment be kept from getting in the system. What little does
make its way in should be removed by netting/vacuuming, diluted or removed
by making partial water changes.
Some potential pollution will probably be added to your system in the way of
food and chemical additives/fertilizer. Even without over- or mis- feeding
and/or fertilizing, freshwater evaporation adds to a decided negative
chemical effect on an aquatic system. This "Salton Sea Syndrome" occurs as
water evaporates leaving behind its' chemical constituents.
So enough of the reasoning for making water changes; onto the nuts and bolts
of how to do them:
How often:
Depending on your pump/filter/circulation system, stocking and feeding
regimen et al., partial water changes about once a week to about once a
month are about right. More frequent smaller amounts are better than
infrequent mega-changes, with one possible exception. Some writers advocate
an occasional massive change (50% or more) as a stop-gap measure to dilute
metabolites, nitrates in particular. I'd rather encourage you to stick to
regular, smaller volume changes; they're safer and accomplish about the same
ends.
Make a schedule/notebook for your system and keep track of what you do and
how it works for you. Patterns will emerge and give you a guideline for how
frequent you should change water.
How much:
Five to ten percent for larger systems and twice that for smaller is
generally sufficient. The chemical/physical/biological shock from changing
too much too soon is to be avoided.
Though some marine authors state that water treatment chemicals are
unwarranted with such frequent small percentage change, I'd encourage you
"to be safe, rather than sorry", and treat to remove chlorine/chloramine
unless you're preparing water a week or more in advance of use.
How to:
However it is achieved, the part of the water and what's dissolved in it are
mainly to be found at and in the bottom.
Solids are systematically removed from part, but never all of the bottom of
the tank and possibly sump by using a "gravel vacuum". We don't want to vent
all the beneficial microbes along with the solids, so a plan is made to move
the decor and vacuum a half, third, what have you, of the base in a given
water change period.
New water is replaced with pre-mixed synthetic of similar temperature and
specific gravity.
Summary:
Regardless of how well a system is designed and constructed, there will
always be maintenance. Frequent partial water changes are one of the best
ways of ensuring continuing success.
There are manufacturers who claim their products do away with the need for
frequent partial water changes. Their products may well extend the amount of
time between changing or ostensibly eliminate it, but at what economic cost?
With the proper tools and materials, water changes are a breeze. Water
changing is the cheapest, easiest, most sure method of diluting wastes and
replenishing buffering capacity, "trace materials", while concurrently
cleaning the system of undesirable solids and liquids.
Bibliography/Further Reading:
Bauman, Edward. 1994. Water wisdom; as if changing a little water will kill
you. AFM 12/94.
Branscome, Lee. 1985. How to stop carrying those buckets of water. FAMA
11/85.
Dow, Steve. 1986. Heavy water. TFH 5/86.
Fenner, Bob. 1999. Frequent partial water changes. FAMA 5/99.
Hanford, Wilber L. 1969. A change of water. TFH 5/69.
Mowka, Edmund J. 1979. Water changes in the marine aquarium; partial water
changes in the marine system are often neglected for a variety of reasons.
Here's why water changes are essential, as well as a method of calculating
the necessary amount. FAMA 12/79.
Ostrow, Marshall E. 1981. Water changes. TFH 5/81.