This is not an exact science, and depending on the overall organic load of each tank will vary among users. Probably the most common product will be Rid-X, so from post #6 by Tom. (Aquanero)
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My experience has been the same as Miguel's and Neil's (RD.). I have been using a product called Earthworm (link attached below) I've also tried Rid-X with the same results. My fish also eat the undissolved pieces with no ill effects what so ever. These products have completely dissolved (eaten) the waste in the tank, kept the filters cleaner and have improved water clarity and reduced/eliminated odors. I have been dosing at a rate of one tablespoon every two weeks per 90 gallons of water however exact measurements are not necessary, along with regular weekly water changes.
I have used this in my 225 with wild Scalare Angelfish, in two 90's with some Oscar grow outs. Other fish that have been exposed to this in various tanks include Festavums, Chocolate cichlids, A Royal Pleco, Eartheaters, Corys, Liopoldi Angelfish, Altum Angelfish, various Tetra species all with no ill effect over the last few months. I was also interested in the aspect of competitive exclusion and the long term benefits. My fish are generally healthy so this part of the equation will have to play out over the long term. As far as the immediate benefits, as stated the tanks "appear" to be healthier overall and water parameters remaining stable. This is the same principle as the "sludge" removers you can buy at a higher price with less of the good "good guys". Take a look at the link I attached to see what these products make available to fight all the nasties in are systems.
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Hope that helps ........
