I discuss metal binding to them here:
http://reefkeeping.com/issues/2003-04/rhf/feature/index.php
Export of Metals: Poly-Filters
Many aquarists have heard that Poly-Filters (made by
Poly-Bio-Marine) absorb copper and other heavy metals. Poly-Filters are essentially comprised of an organic polymer that is designed to bind to a wide variety of chemical compounds in aquaria. As with all materials that bind metals, the higher the concentration of metal in solution, the more metal will be bound. Unfortunately, this fact has lead many aquarists to misunderstand whether Poly-Filters might actually help them reduce metal levels below that present in typical reef aquaria (10-40 ppb). In this section I am not discussing whether one can make a polymer that will bind copper and other heavy metals from aquarium water (that's a different discussion for elsewhere in this paper and others, but it is possible that modified Poly-Filters might work in that context). What we are interested here is in whether there is any information to suggest that currently available Poly-Filters are effective at reducing the copper concentrations below the 10-40 ppb copper reported for all of the marine aquaria in Shimek's
study, and in my own aquarium (10-13 ppb copper).
It turns out that, unlike most manufacturers, Poly-Bio-Marine provides some
nice data and makes the results especially clear for us. Unfortunately, what they say is that it won't work for many metals in artificial seawater. In fact, they have specifically designed these filters to not take out copper below 30 ppb. Here's a series of quotes from their
website:
“ASTM Standard D 1141 lists only six (6) trace elements which are : Barium (99.4 mg/L), Manganese (34.0 mg/L), Copper (30.8 mg/L), Zinc (9.6 mg/L), Lead (6.6 mg/L) and Silver (0.49 mg/L).”
Note: mg/L is the same as ppb (parts per billion)
Then they note:
"Our next section will go into details of how Poly-Bio-Marine, Inc.'s special manufacturing process prevents Poly-Filter from sorbing those trace elements and other major or minor synthetic seasalt components."
"In order to make a Poly-Filter not capable of sorbing trace elements we must first saturate each Poly-Filter with the trace elements found in synthetic seawater."
"Upon completion Poly-Filter will not sorb trace elements nor calcium, magnesium, strontium or fluoride."
So they add the metals listed above to the Poly-Filters during manufacturing in order to prevent them from bringing down these metal concentrations when used in aquaria. In reality, I don't know whether their statements are accurate or not in relation to real aquaria, because all of the tests were in freshwater and synthetic seawater, not in aquaria where some of these metals (especially copper) will be largely bound to organics. Nevertheless, taking their claims at face value, one is forced to conclude that Poly-Filters will not be generally useful in reducing metal concentrations below the levels shown in Table 8 when used in raw artificial seawater. In this case, only zinc appears to be at a level such that Poly-Filters will remove substantial amounts from aquaria.
It is entirely possible that these filters will be more effective than described below at removing metals when the metals are bound to organics in real aquaria. After all, these filters claim to remove organics as well. However, it is also possible that they won't be effective, and testing them under actual reef aquarium conditions is something that I hope to provide in future articles.
Table 8.
Removal of Metals by Poly-Filters.
Metal
