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RE: Algae issues/green dust



> Date: Fri, 01 Nov 2002 21:15:09 -0500
> From: Thomas Barr

> David,
> Do you have something along the lines of what's
> been called "Green Dust"?...

Up 'til now, the tank's only been bothered by two types - an early bout of
BGA that usually occurs in my tanks with wood, and the normal "30 day brown"
attack with some new setups. A single dose of eurythro and a couple daily
water changes stopped the first, and the otos erased the brown. Any other
algae has been relatively benign, as I tend to let the "furry" types cover
the wood in a few tanks. I call them "benign" because they prove quite
decorative at times and always seem controllable (stay to the wood and not
easily spread to the plants).

But with the appearance of this algae I _have_ begun to see some "spot"
algae on the glass (the type growing in nice little dots that takes
sandpaper to remove)- something I almost always expect to see when
conditions are good, but haven't been seeing much of in a couple of years.

> Namely grows on the glass and grow back almost
> as fast as you wipe it off? Doesn't really grow
> on the plant much etc?

If I had to hazard a guess, I'd say that it easily reproduces within the
water column as "dust", but once attached becomes more "cottony". But since
the hair grass is the only plant to which it seems attached, it may simply
be this bothersome algae getting caught up in something that came in with
the grass. On things like the R. wallichii, L. arcuata and Red Ambulia it
siphons right off like simple dust. The broader-leaved plants don't show any
traces of it at all.

What it does to the water bucket is something else, too. When siphoning the
plants clean, the water in the bucket ends up looking like you've just
washed the detritus out of all your filters in one bucket. Except for the
color - this stuff displays an intense rusty red in a white bucket. So it's
growing and settling out of the water pretty rapidly - it's hard to picture
something that's both benthic _and_ "dusty" simultaneously...

> If so, I believe it to be a zoospore green that
> can reattach back after being scrubbed off.
>
> That's how it comes back so dang fast...
>
> But after you scrub, do a water change then run
> a micron filter/diatom type filter or run a UV...

I might try picking up a UV.

In this tank, the water's starting pretty clean. This 38 holds a working
volume of 30 gallons (after aquascaping, etc.), and when changing it out I
initially draw off three 5-gallon buckets, cleaning and scrubbing while
draining. I then refill 5 gallons, draw another 5 gallons, and repeat this
to rinse out the remaining 50% of the start volume. The tank is then
refilled from there. (I settled on this type of "water scrubbing" when I
first learned to handle Green Water, and this pattern will reduce the
concentration of any water-borne contaminants down to about 10% of initial
levels without doing so too hastily to disturb the tank's inhabitants. Next
best thing to a 100% change without the shock.)

Unlike Green Water however, which is almost always knocked out by just two
or three days' worth of this routine, this algae has survived almost two
_weeks_ of this treatment and recuperates from such low concentrations in
just 24 hours. So I've settled on doing water changes every other day, time
permitting, and at least it doesn't get any *worse*.

So a UV unit might be worthwhile.

This seems to be about as close as I've ever come to a "Mexican Stand-Off" -
it's not yielding, but neither am I...

> I did try to inoculate a tank once with
> some fresh zoospores but I think the
> transition was too much for them. Perhaps
> they needed a slow acclimation:)

So far, this hasn't appeared in any of the other tanks, most of which were
established this time last year when I moved here...


-Y-