spidey_webb wrote:
Hi all,

I recently had a problem with my filter and while cleaning it I found A
couple of conical shaped shells in the filter media. It has been less than
two months since that problem and I started having the filter problems again
and this time I noticed quite a few more of these conical things. They vary
in size with some being as long as a quarter is wide. They are a dark brown
or black and seems to be something living in the shells. I don't know how
they got introduced and I am positive that they were not all introduced by
me which leads me to belive they are growing in the tank and somehow
producing their on shells.

I am sure this is a sort of Malaysian Trumpet Snail (MTS). They can vary a
bit in color and the young ones are much "pointy-er" than the adults. They
are livebearers which live mostly in the substrate. They do tend to come
out of the substrate at night. You can try making a "snail trap" by
putting a saucer with some sinking algae waffers on a clear part of the
substrate and see how many come out to eat. Some also recommend using meat
to trap MTS, although I'd take care doing that if you have mbuna or other
veggie cichlids.

MTS have a nasty habit of invading filters, particularly sponge media. One
way to prevent it is to put a coarse sponge (like what AquaClear uses) on
the filter intake. It should be coarse to allow water to flow fairly
readily through it, but still be able to trap the snails. Clean that
sponge often and replace it if it becomes clogged with snails (or anything
else). You should also take the filter completely apart and clean it out.
You'll probably find bits of shell in your impeller if your experience is
anything like mine. Plus there will probably be many shell remnants in the
bottom of the filter housing. Just clean that all out. It affects the
amount of water your filter can move. Of course, preserve the bacterial
colonies on the actual filter media. One way I did this was to just
repeatedly squeeze the sponges (I use a dual sponge method on my MTS
infected tank) in a bucket of tank water and I also manually picked off as
many of the snails as I could. Doesn't get rid of all of them, but greatly
reduces their numbers. Eventually, you'll have to replace the sponges most
likely to keep the water flowing, but do it in a way that won't completely
wipe out your bacterial colonies, like if you have two sponges, replace
one then don't replace the other for several weeks. Other types of media
will need other methods of course.

You'll probably have to repeat this cleaning of the filter (especially the
impeller) for several months to get rid of the last of the snails in the
filter. It gets rather annoying. On the plus side, the sponge on the
intake is great if you also have fry in the tank. Prevents them from
getting accidently sucked in. Also, it helps prevent other large matter
from getting into the filter. For example, my 40 gallon tank also has java
ferns and the broken off young plants often get drawn to the filter
intake. With the sponge, I can pick them off the sponge and put them
elsewhere. Although, it doesn't seem to help with my crypts that want to
grow into the intake, heh.