I think you should give it a try and let us know how it works. Personally i wouldn't use it on a regular basis even if it works, but it may be good to use before going on a vacation or other times when regular weekly waterchanges are not possible.
One of these days I'll get around to testing this stuff myself, just have to set up another tank to do it. You may want to look into using the Instant Ocean version of this product as it is more concentrated. Tetra and Instant Ocean are sister companies, along with Marineland.