Remove the foam from the canister filter and keep the biomax and carbon.
The bacteria that eats nitrates is anerobic and only lives in very low oxygen enviroments like a denitrator or deep sand bed, my personal experience says that DSBs are useless and more problematic than they are worth(I'm sure some will argue), the other method is to grow aerobic bacteria(lives in oxygen) with a carbon source ie, biopellets, vodka, sugar or vinegar dosing, by growing the bacteria nitrate and phosphate are used are used up building the cell walls of the bacteria, the bacteria dies and gets removed by a skimmer thus removing the nitrate and phosphate from the system.
You must have a good skimmer for this method. Growing macro algae will work to, but that requires a lighted refugium and is somewhat limited to amount of nitrates it can take up.
I think the simplest most effective method you could employ is vinegar dosing, read this.
http://reefkeeping.com/issues/2008-08/nftt/index.php
IMO sulphur denitrators rule.