[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Black Algae

Stephen Druck wrote:

>Please HELP !!!! I have a 640 litre fresh water tank with
>about 16 fish living. I have had the tank for about 2 years
>and have been very happy, up untill recently.

>About 6 months ago black Alge started growing in the
>tank. It resembles tiny black dots but after a week or two
>turns into black fluff and eventually destroys the plant that
>it was on. The algae is also found on the inside filters and
>rocks but not on the glass.

This sounds like an outbreak of the dreaded red algae, which
sometimes looks like black hair growing on the leaves of plants.

>My PH is correct at 7.0

Are you injecting CO2 to maintain your pH?  I hope you aren't using
a phosphate-based buffer product, because if you are that would
explain the problem.

>the amonia and nitrate tests are all ok.

What do you mean by OK?  Remember, you should have about 5-8
mg/L residual NO3 in your water.  If your tank is nitrate limited, or if
there is an overabundance of nitrate, all kinds of bad things can
happen.  As an aside, the better nitrate test kits, such as LaMotte,
measure "Nitrate as Nitrogen".  To arrive at the actual NO3
concentration, the number derived from the test must be multiplied
by 4.4.  The 5-8 mg/L range is therefore something of an estimate.
Also, check your iron levels.  Inadequate iron (< 1.0 mg/L) will
deprive your plants of their ability to utilize available nitrates and
phosphates allowing the algae to establish itself.  Too much iron,
however, will cause other problems.

>I also have 2x3foot and 2x2 foot triton lamps. I did change these
>globes but that did not help.

This sounds kind of feeble to me, especially if you are using only two
lamps, but if it has worked for you for 2 years I don't see how it can
be causing the problem.

>Water changes haven't helped, nor have anything tried
>from my local pet shop.

It's this last part that worries me.  What did they sell you to throw in
there?  Whatever it is, stop using it.  Keep up the water changes.  In
fact, you should probably increase their frequency. Get a handle on
your nitrate and iron levels and adjust them accordingly.  If you are
not injecting CO2, I strongly recommend that you consider doing so.
Sorry I can't be more helpful than this, but it sounds to me like a
water quality problem or nutrient imbalance.

Good luck,


Energetics, Inc
7164 Gateway Drive
Columbia, MD 21046
(410) 290-0370

For problems with this account please 
e-mail admin at energetics_com