"GaneaRowenna" wrote in message
...
Newbie in Newsgroups but not testing posting.

UK based, years of experience in all sorts of aquatics and also a year in
industry testing chemicals.

Really, any inert material will do for filtration, either mechanical or
biological, the first to kill the flow speed and settle the solids, the
second to provide a huge surface area for all the bugs to munch away on the
waste. If you're worried about the cooler pad (whatever that is), shake it
up hard in some water and see if it forms a persistent surface foam. If it
does, I'd avoid it. Alternatively you could put some in a bucket with a
small fish for a week. Don't feed (to avoid pollution). What's it made of?
Did you know they used to sell glass wool as a filter medium? Can you
imagine the damage? Totally unsuitable! If the fish doesn't show any obvious
distress then it's probably OK BUT DON'T BANK ON IT.

I've used polypropylene garden shading as a filter medium for years without
any obvious problems.

Got algae? Fit a new filter in the system, with aquatic plants, but watch
the roots don't block the outflow, and they'll take out a lot of the
nitrogen. They use the same system at sewer works. Grow plants, not algae!

Regards to all ponders, Mike.