"Desmond Wong" wrote in message
...
Hi,

Any ideas on the best way to clean a second hand tank? I have aquired
one,
and found that because the previous owner kept it only half full, the
bottom
half of the tank is quite clean, but the top half has this white
film-like
substance on it.

I have tried using water and a razor blade, doesn't seem to lift. What
would
be safe to use on it to rid this stuff?

Des.

Wow, you sure got a lot of good responses. This must be a topic everyone
has lots of experience to share. With so many responses, I might just
stop posting my comments, - not ;~). In case anything was missed, here
is an old reprint of a post I wrote on the topic:

Depending on the chemical composition of the stain, and the quantity of
build-up, you might find vinegar useless, but it's a good first choice as
it is easy to deal with residues. There is a wide variety of techniques,
some more appropriate for glass tops, rather than to try using inside the
aquarium as their toxicity increases with their cleaning power. Other
methods I have read of besides vinegar (white distilled works best), are
salt (kosher salt more abrasive on stains), lime Kool-Aid? (half the
water & no sugar), dish soap (contains acid) with nylon scouring pads,
bleach, CLR, lime away, tile cleaners, #000 (fine) steel wool, razor
blades, sulphamic acid, and muriatic acid (hydrochloric acid). A search
on the internet will also turn up an assortment of miracle products which
will peel the paint off your barn door at 20 metres ;~)

Note that all the mechanical methods (razor blades, steel wool, scouring
pads) pose some risk of abrasion, if not from what you are holding, then
from the deposits you are trying to remove if they get trapped in
between.

The more aggressive the solvent used, the more hazardous the work. If
you go as far as using strong acids, it's prudent to be prepared for any
spillage. One poster suggested baking soda (sodium bicarbonate) to
neutralize any spills, "if you dissolve a couple of cups in a gallon of
water you can immediately neutralize spills on your equipment or skin ;
straight powdered baking soda may react violently with concentrated acid
and splatter you or nearby friends". Wear glasses, please, goggles if
you have them. From vinegar to muriatic acid, none work instantly, so be
prepared to let them soak as necessary.

Many of these suggested treatments were pulled from the Google usenet
archives (I personally have no special tricks, and I haven't tried all
these treatments). Another option for top plates with hard water stains,
is to drop them off at a glass supplier. He will measure and provide you
with duplicates. Use a little clear silicone & rubber handled clamps to
fasten the retaining edges back on. The glass is typically quite thin,
so the material is not very expensive.

cheers
--
www.NetMax.tk