"~ jan JJsPond.us" wrote in message
...
A club member has a problem with this black slimy bacteria (Cyanobacteria)
in his planted, few fish aquarium. He has treated several times with
Erthromycin and it comes back. Any suggestions? ~ jan


~Power to the Porg, Flow On!~

Several factors influence the growth of cyanobacteria: 1) nutrient/organic
debris load too high; 2) levels of dissolved organic carbon are too high (DOC);
escessive phosphate levels; excessive lighting or lighting that stays on too
long. Cyanobacteria is easy to remove, but difficult to control. In order to
bring cyanobacteria under control, the aquarium must be cleaned thoroughly
(note: algae and cyanobacteria will grow faster in a squeaky clean aquarium than
one where some algae/bacteria is left to grow, such as on the back of the tank
glass. This is because a clean aquarium reflects more light which facilitiates
bacterial/algal growth. This is what I do, and it seems to help). Since
cyanobacteria are photophiles or utilize photosynthesis in order to grow, the
amount of light the tank receives should be dramatically reduced for several
weeks. An organic chemical such as Boyd's Chemi Clean can also be added to the
water to inhibit the growth of cyanobacteria (careful with invertebrates that
are symbiotic with cyanobacteria). Several treatments may be necessary before
the problem is brought under control. Using erythromycin can do more harm than
good since it can kill off the beneficial bacteria in your filter and tank and
actually make the problem worse, since unwanted nutrients such as ammonia,
nitrites, nitrates, and phosphate levels will rise.

I hope this helps.