Why
hair/blanket weed algae will never be cured
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The list of common and local names goes on. Some from the aquarium industry,
and many from the water garden industry. The trouble with this of course,
is that one man’s blanket weed is another Gal’s string algae.
And the string algae in ponds doesn’t look like the hair algae in
fish tanks! Add to this confusion, the fact that the real koi hobby is
probably only the top 15% of all people in water gardening. So it is natural
for these small numbers of individuals to ban together for information
sharing purposes. This is not limited to country boarders and we find
that hobbyists from Japan, Holland, Belgium, Germany, England, South Africa,
Singapore, Taiwan, Phillippines, Canada and The USA all talk to one another
and often use these common terms.
So quietly ( and rapidly), and given the fact that there are over 8,000
known varieties ,these species flourish in the confusion!
Let’s take a look:
1) Slime algae is an easy one. It is called SPIROGYRA.
* it is usually a raft of green, but often ‘looks’ attached
to walls because it drifts.( this algae will sink and rise in the water
depending on photo synthetic phase)
* it is light to medium green in color. Kinda pretty green if it wasn’t
so annoying!
* It is slimy to the touch, and very soft.
* holds gas bubbles, from photosynthesis and for buoyancy regulation,
within its mass that are clearly visible.
* of the three it will have the strongest odor.
* this should not be confused with the true blue/green slime algae which
are actuallynot algae at all but rather Cyanobacteriales- I.E. a bacteria
that has photo synthetic abilities.
2) True blanket weed is not hard to spot either. It is called PITHOPHORA.
* It is very course to the touch and therefore gets horse hair or wool
algae names.
* It is the only one of the three that will grow off the pond bottom as
well as the sides. ( although Cladophora will grow on stream bottoms and
water fall bases.)
* It varies in shade from yellow/green dark green to green/brown
* Is very rapid growing when conditions are ideal, in fact fastest growing
of all except The unicellular forms.
* It is seasonal in the wild but can survive open ended in captivity.
* When it is in all its glory, it indeed looks like a veggie rope!
3) String algae or hair algae can be one of two dozen green filamentous algae. And some in this group are very desirable. The one we deal with most frequently as a run-away nuisance is called CLADOPHORA.
* A very lovely light to ‘grass’ green in color. It leaves
the impression of being fineor even delicate. But like some Southern Gal’s
I have known- it ain’t so! Tough as nails!
* On the ‘feel’ meter, it is more cotton-like in texture.
* it is also rapid growing and likes unstable water conditions and rapidly
moving water.
* It’s fine strands are seen in water falls and near pond water
returns.
* capable of growing a few inches a day in summer.
* unlike Pithophora or Spirogyra, koi will work at Cladophora if no other
food is available or during ritualistic schooling behavior. Only very
new Pithophora orSpirogyra will be consumed by koi. Otherwise they will
only feed on the particles ON those forms and not those forms themselves.
You will see them tear at but spit out and swim away from torn off pieces.
So now that we at least see ‘The Big Three’ as not one but
a group, what good does that do us?
Lots, now we can discuss of the triggers and reasons for explosions in
individual ponds. Everyone wonders why they get one of these algae in
their ponds- BUT they never seem to wonder why they only get one and not
all at the same time! And why, once bitten, the same species seems to
come back again and again!
This of course is a subject for an entire book. We can take them one at
a time and see if anyone can supply hints along the way. So if you see
a REASON that might explain why you get one of these, please pipe in.
JR
Part II
So we have a group of three that seem to appear either in initial stages
of a pond set up or after a full season. This is a different dynamics
from the one we see with planktonic forms of green algae that deliver
up green water. There are a couple of reasons for this;
1) algae does not appear in a vacuum. They are opportunistic
and omnipresent. It is their role within the overall pond biology that
is the key to limitation. Like competitive exclusion of certain heterotrophic
bacteria species, having the correct algae often means - excluding the
incorrect species from establishing.
2) if bacteria species are in competition, then surely
algae species are in a war! They actively try to dominate, and in doing
so, knock the others out of a major role. This can be seen in a new set
up ,especially during new pond syndrome cycle. You can first see the gold/brown
diatoms and lower algae forms, the competing ‘good’ greens
and some red cyanobacteria ,and then the start of the bad guys. Depending
on many factors such as heterotrophic bacteria presence, nutrient in the
form of inorganics and organics, gas levels and micro nutrient in the
water, some one is going to get a tactical advantage. What we want are
the short growing and eatable true green filamentous forms. What we do
no want is the Big Three.
3) the AMOUNT and TYPE of nutrient will be key as to
whether you see green water or filamentous algae. All algae is limited
by whatever needed nutrient is in lowest supply. This is a limiting factor.
Green water , as mentioned , is made up of billions of unicellular phytoplankton
cells. They are always lurking but can explode seasonally with a SMALL
amount of the correct mix of nutrients in the water column. Filamentous
forms like the Big Three, come when LARGE amounts of nutrient are always
present. In a struggle between the two however, filamentous forms win
the day. This is because the become self sustaining over term. The planktonic
forms on the other hand, tend to be cyclical and non enduring.
4) The Big Three are blessed with an astounding number
of reproductive mechanisms ( budding, spores, sexual repro) and at the
same time have ways of passing on captured nutrient to new generations
of cells. They can, once becoming the dominating form, incorporate bacteria
to become part of ‘their’ definition of the carbon cycle.
Truly impressive survivors!
Being wrong headed?
Trying to poison these forms is the usual recommendation. Copper based
products being the oldest standby. But Pithophora will not allow copper
to penetrate the deep cells and therefore can not be killed this way.At
the same time, all the good algae that holds the line against a complete
domination of the weed, is definitely killed! Leaving the system free
and open to a complete take over by teh weed forms! And once established,
this forms are very very to get completely rid of. Spirogyra being probably
the easiest one to get rid of and the other two being the most persistent.
The dopey approach of adding rotting straw to a pond with fish so that
the anaerobic process and the resulting metabolites will kill algae cells
is so dump as not to deserve comment. And the constant quest to find some
creature that can be depended on to eat all the offendering vegetation
as it appears is futile and unrealistic over the long run.
The correct approach should be to KNOW the enemy and make it impossible
or unlikely that such species can do well in the right environment.
What are those conditions?
| The ones the Big Three like? | Where do these things come from? |
They love high nutrient levels. *On the inorganic
level- Nitrate , nitrite or ammonium |
*
your tap water ( may contain phosphate, nitrate etc) * fertilizers - you can turn you water green by misting your pond surface with liquid fertilizer every day! * the dynamics that takes place when koi are overfed rich diets that contain phosphorus, Iron or potassium. * the natural gas dynamics that occurs when water warms and oxygen levels drop * under aeration. * allowing decay in a system that does not allow mineralization. * allowing for excess mineralization. * and over active nitrification system and no water changes. * excess addition of minerals and hardness to the water * high pH in the presence of nitrates and algae friendly minerals. |
The problem I have with the general approach is both philosophical and
practical. I want a pond that is bullet proof in terms of stability. So
warding off algae with additives is , to me, a sign of system weakness.
My pond is in full sun. Have not had green water since Reagan was in the
white house. Have not changed bulbs in the UV units since before Clinton
was 'dating' Monica. Not bragg'en! Just saying that when a system is mature,
in equilibrium and stable, there is no place for algae blooms, aeromonas
counts, parasite explosions etc..
The second thing, and the very last thing I want is decay. It is an ORP
killer, a drain on alkaline reserve and a burden on the BOD. The rotting
of straw does produce a fascinating benefit in either the metabolic toxins
of the bacteria or the bacteria themselves. Interesting. But not in my
pond! Because decay also produces species of bacteria near my fish that
are definite 'trouble makers'. No need to tempt mother nature or fate.
Part III
Once a sytem is inoculated it takes some real effort to dislodge it as
it seems to return again and again.
I still fell it is worthwhile for every hobbyist struggling with The Big
Three, to have their tap water along with a sample of the pond water checked
for the follow:
From here, check your fish food for phosphate (phosphorous) and magnesium content.
After this workup you will know if your pond needs to be bleached as the only way to stop the infestation.
I think its safe
to say that there are two different conditions when it comes to these
weeds-
1) the approach that assures you don't get any of
The Big Three. IE preventative
2) the detective work and the action taken when you do
have it.
As difficult as it
is to try and put the green genie back in the bottle, you will never be
successful if you don't track down the limiting factors and the excesses
in the water. I would check the ponds phosphorus when you are feeding
heavily. On your tap water look for orthophosphate. Dying algae will certainly
release this back in the water.
Nitrates would be the second thing I would look at. The difference here
between start up infestations and the continuing fueling of existing weed
is
1) in the start up it is more likely nitrate that kick
starts the weed as its nitrogen source
2) in the established stage weed can use ammonium, nitrite
and nitrate and rob the bacteria for their nitrogen needs.
Magnesium is absolutely an essential component of chlorophyll yet alone,
is not much a limiting factor in the short run. And calcium is also needed
but easy to get. Total hardness is the measure you want to see, as the
ratio of monovalent and divalent cations may be a key.
And of course, the more you kill all other forms of algae, the large the
'hole' for undesirable species to take up the remaining nutrient.
JR