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I have a brown algae problem. I know that this can be from high phosphates. So why is my phosphates levels high and how can I bring them down?

Hi,
High phosphates can be caused by the foods being fed to the
fish and over feeding. It can come from your tap water.
It can come from poor maintenance (insufficient water
changes and little or no gravel vacuuming).

That being said, "Brown Algae" is generally an outbreak
of diatoms. This is normal in a newly setup tank in which
the owner has used silica based gravel, large amounts of
silicates for hard scape, or even from your tap water.
Older, established tanks can also have outbreaks and again
the cause is an over abundance of silica.
Additionally there is usually poor lighting (incandescents)
or low wattage per gallon ratio.

The diatoms thrive on excess silica and "explode" throughout the tank.

To resolve the diatom outbreak, you will need to do
frequent water changes (assuming your tap water is not the
source) and include vacuuming the gravel. Increase your
light to 1.5 or 2 watts per gallon, and use only lights
that are rated at 6700K or higher (not over 10,000K).

If it is phosphates, check the breakdown of the contents
of your fish food. Most of the time you will find
phosphates to be one of the ingredients, and change to one
with a smaller amount or no phosphates. Again, assuming
that the phosphate is not in your tap water, do several
small water changes and vacuum the gravel at the same time.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Thanks Frank,
My flake food and algae discs have phosphates in them. I will know look for phosphate free food.
I think that I will also go from 1/6 water change 2 times a month to 1/6 water change a week. As I have Oscars and they eat like pigs.
You also said that I should use a light that is higher then 6700k but lower then 10000k. Why?

Hi,
One of the things that diatoms prefer is a lower light
level. 1 or 2 watts per gallon in the lower K range
4000-5000 light is yellowish and dim. In the 6000 to
10,000 K range the light is white and is brighter. This is
great for plants, lets humans see the true colors of their
fish, and puts a crimp in the diatom paradise of a dim tank.

The reason I cut it off at 10,000 K is because as you go
from 8800K up, the light tends to shade toward the blue
end of the spectrum. That can washout the greens of the
plants, and is actually, really, harsh for freshwater plants.
Salt water plants and algae's however, just LOVE light that
is 10-20000K and over. It brings out their colors and the
fish's colors, and also provides the necessary light for
the various forms of algae that give clams their colors
(for instance).

When I was raising Oscars, I did a 50% water change each
week. I tend to suspect that your 1/6 of a tank is too
conservative (bordering on way too conservative) and
is allowing the phosphate and perhaps the nitrate to
build up.

Once the word got out (my kids to their friends) each day
we had an endless supply of "bugs" to feed them. The kids
would bring their catches in, drop them in the tank and
watch the fish eat. Lucky, were the grasshoppers and
crickets and worms, that the kids missed.


Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--