All of the bead filters, converted sand filters, use polyethylene beads.
The specific gravity is just less than 1.00 and as such they float and the
water flowing up through them is filtered nicely. Being near the same
specific gravity as water, they are easily backwashed, with the tumbling
action getting all of the material filtered sent to waste. Someone on here
was looking for a source several months ago.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html
"Mark Bannister" wrote in message
. ..
As a plastics person I can tell you that almost all plastics will be
safe for fish. Some products may have surface contamination. Wash
thoroughly. Food grade plastics typically are rated such because they
are safe when exposed to heat, acids or oils that may be in food. These
may cause chemicals to leach from the plastic.
As mentioned the only issue you will have is UV stability. Keep it out
of direct sunlight.
Mark B.
PS: Speaking of plastics, since I am in the plastics business I have
access to plastic pellets. I've noticed some filters use them usually
as a prefilter. Any experience out there? Pros? Cons?

Perry wrote:
Hello All from a first time postee,

I am making my first foray into ponding. I'm familiar with the products
and
techniques, but have never actually used them. To practice, I've bought
a
large Rubbermaid type storage bin from Wal-Mart which I intend to
disguise
well and stock with literally one or two small mosquito fish or tadpoles
from a nearby pond.

My question: Does that type of plastic emit any dangerous chemicals or
gases into the water that would poison flora or fauna? I'm not looking
for
long-term quality, just short term practice.

Thanks.