Q:
My wife and I went on the
pond tour; we had seen ponds that had whitish foam around the waterfalls and
around some of the rocks nearby. The bubbles that this foam made took a long
time to pop, what is that foam from? Is it bad for the fish in
our ponds?
A:
The foam is a mixture of
oils, proteins, fats, and other organic compounds that accumulate in the pond
water. Some of the foam will derive from your fish and from the decay of
uneaten fish food and some comes from the breakdown of plant debris and algae.
The
foam commonly found around the base of waterfalls, with the physical actions of
churning water causes the substances to break out of the water column and
coalesce as foam. If the majority of compounds that comprise the foam come from
plant decay, and/or plant matter, the problem is unattractive but not that
harmful to the fish. However, when the majority of the compounds originate from
fish sources, it can become very hazardous to the animals in any aquatic
system.
Studies
have shown that fish kept in water polluted with fish-derived dissolved organic
compounds suffer a higher rate of disease and parasitic infestations and do not
grow as sound as fish kept in water with substantially lower concentrations of
the substances. The concentration of these substances will also lower the redox
potential of the pond waters and substantially decreases the ability for the
water to carry oxygen.
Because
there is no easy way to tell, whether the foam in a pond is fish-based or
plant-based. The higher the fish load in the water body proper, the greater the
likelihood that the substances will be fish-based, and are a potential cause of
fish disease problems.
This
is why some of the higher tech ponds will install a foam fractionator, which
will remove the dissolved organic compounds from the water. Ozone may also be
used as a supplement to the foam fractionator to help remove the organic pounds.
A
normal molecule of oxygen (O2) has two atoms, and ozone (O3) has one additional
atom. The extra atom is highly unstable and is an intense oxidizing agent. The
main reason for its uses is to eliminate unwanted dissolve organic products by
increasing the systems redox potential and applies to a sequence of chemical
events in which elements and compounds transfer and/or rearrange positive and
negative electrons. Elements and compounds that want to gain an electron are
“reduction agents” and have a negative charge. Those that want to give up an
electron are “oxidizing agents” and have a positive charge. Measuring the effectiveness
of this process by its minute electrical charge it generates in millivolts (mV)
with an Oxidation Reduction Potential meter (aka: ORP meter). We must also
remember the effluent from an ozone contact chamber must be passed over a bed
of activated carbon to remove residual ozone before it returns to the pond.
Even though residue ozone is short live, usually less than an hour, the residue
can damage fish tissues and other inhabitants of the pond plus reduce its
natural fauna.
In
addition, ozone does not add dissolve oxygen in the pond water, at least in any
significant quantities that would benefit any of the pond inhabitants.
Depending upon your pond husbandry practices, it is very possible to get by
without it. However, before any hobbyists turns to its use, increasing dissolve
oxygen in the pond by increasing water circulation, reducing bio-load, trying a
more efficient and/or better designed filtration system, and increasing the
ponds general maintenance level, seems to be preferred over ozone usage.
A
disadvantage of the foam fractionators (aka: Proteins Skimmers) is that some
beneficial organic and inorganic trace elements are also removed. So systems with efficient protein foam
fractionators must be monitored for loss of these elements. This skimming
process does not work as well in freshwater, due to the almost neutral pH, and
this reduces the electrical interaction between organic molecules and water,
which decreases foam fractionation. In addition, the lower density of
freshwater reduces the formation and stability of tiny air bubbles (the
addition of salt may be needed). The only time foam fractionation and ozone is
to be used, is when the stability of the pond is in question.
A
fractionator can be very beneficial to the pond, but it does not fit within the
modus operandi of every pond enthusiast. It has to be cleaned, adjusted,
and cared for on a daily or weekly basis, or else it will become useless.
Two different sizes of Clarity Protein Skimmers for pond use;
not only are they big but also must be hidden from view somehow from onlookers.
They are only necessary for those that have high organic waste from dead
plants, over feeding, too many animals in ones pond, inadequate filtration and
bad husbandry. These two expensive
protein skimmers will help cover-up ones mistakes but they will not correct
what is wrong in the first place and are only a Band-Aid in pounding…not the
cure!
Photo taken from Internet.
As I wrote this I decided to run outside and take a photo of
my ponds waterfall -above two photos- to see if there was any protein bubbles…nope! That’s why my
TDS, CE and Redox are so high in my pond because with proper husbandry and with
the Anoxic filter I don’t have to worry about organic waste buildup.
Anoxic Filtration System ®
February 02-2005-2013
New Updated Version
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