Ironically, I just threw away a load of old leaflets I found in a drawer tonight. These are the Tetra leaflets advising exactly as on this site.
Personally, I can't agree that adding a chemical to the water will reduce the amount of water changes necessary. I did try this product on my previous tank, but was too frightened to cut back on water changes. My tank was overstocked, and I was carrying out bi-weekly water changes, this product had no impact at all on the build up of nitrate even though I did not cut back on my usual routine.
jrd, I would advise you continue to shift the gravel to release the debris since it does not settle on the surface (as it does with sand).
They advise on this site to change 25% every month, most people do this weekly (though there are mixed opinions on this, I prefer to refresh the tank weekly - or more when necessary) The idea of leaving a tank a month, never mind six months (having used chemicals) concerns me somewhat.
I don't think the site offers bad information to someone who may be completely new, and who may have otherwise not considered any kind of care routine at all, but I think it is basic if you want to really make a good go of fishkeeping.
Just MHO.
