DPH Tank Cyano Bacteria or Not and What to Do About It
written by: Rob Charite
date: 31 August 2000
After a good and detailed investigation I came up with the following,
(although I could be wrong) :) cyano bacteria mostly occurs in badly
maintained tanks. You can recognize the first signs by the smell of rotten
eggs due to poor bottom substrate conditions. When you poke the bottom
area with a stick or what ever you see bubbles rising to the surface.
Mostly in places where the water's flow rate is very low. In bad
situations it could cover all the plants, wood and other possible
ornaments. Since the tank doesn't show any signs of the cyano bacteria it
must be something else. So I roamed the net a bit, asked here, read there
and came up with the following.
Cyano bacteria species are free floating and the colonies that do not
attach to surfaces can "fix" nitrogen gas. They take Nitrogen
gas (from the air) and transform it into nitrates or ammonia and release
those into the water!!! :( This is why Blue Green algae is so hard to get
rid of, it can feed itself. Cyanobacteria also needs Phosphorus, nitrates
and trace minerals to grow. That, and light!!!
The problem now isn't cyano bacteria, but "good" green hair
algae, the "dreaded" algae mostly common in healthy tanks. So
the first thing I did was decrease the light 4 hours a day maximum. I can
tell you that helps, but only for a short while 'cause algae don't need
much light and reappear within one week. So back to nothing, I decided to
increase illumination to it's full potentional, yes, the full 12 hours
with a total of 150 watts !!
Why? you may ask :)
Well, let me tell you this: plants suffer from the lack of light and algae
loves suffering plants as a home. So instead of attacking the algae I
decided to give them what they want :) nurture them that is. Mean while I
bought a new filter, nice one, with a bigger flow rate and bio surface.
What happened is the following :)
I increased the CO2 injection to its limit (almost) that is 23 mg/l with a
KH of 5. The result was a pH of 6.8 that was the max. And added 8ml iron
fertilization every other day and I was really amazed; the plants love
this !!! Why 23 mg/l ? Fish can't cope with levels above 30 mg/l and will
suffer from CO2 poisoning and since I adore the safe side I kept the
amount at 23 mg/l. Using the CO2 and iron as fuel along with the nitrates
and phosphorus they grow like hell.
I can tell ya algae don't like that !!!!
So the only algae that is left is some "dreaded" algae, (nice beautiful
green when kept short by an ancistrus) and some free floating tiny hair
algae (aprox 2 - 3 mm in size) which I am not sure what it is (update
later) but it can't be bad 'cause it isn't blurring my water or affecting
Meanwhile, the tank is crystal clear again and back to his original
state, although I changed some things. So the moral of this story is: :)
when keeping a planted discus tank it is very, very, important to take
proper care of your plants 'cause they are the key to failure or success
and they do have a lot of influence on the water parameters and therefore
the fish !! Needless to say the maintenance regimen is important too, for
both fish and plants.
Rob Charite & Walter Soestbergen