My spreadsheets are all based on the premise of using gravel vacuuming in conjunction with water changes, but the RWI factor is not. As I mentioned in the post, the RWI factor is simply a comparison based on frequency and percentage. Consequently, things like like plants and the specific cleaning routine will make a difference. Unfortunately, those kinds of computations are somewhat lengthy and I did not want to give new aquarists a ten-mile chart to sift through. As such, the spreadsheets use the added benefit of gravel siphoning but the chart is an independent consideration.
Lol, the longer I live, the more I am convinced that life wasn't meant to be simple. :)
Good point about the fish urine problem. The sad fact is that I have not found a good source that discusses fish waste in its consituent compounds. If you know of a source that deals exclusively with fish waste (in compounds, not elements), I would be more than happy to use it instead of the sources currently on the site. I only used terrestrial urine data because I could not find another. Excellent point.
Yes, some urine components can enter a gaseous state and are thus not much of an issue, but not all (by any means).
The chart is accurate regardless of type of tank as it is only the RWI factor. If you keep less fish than average, have live plants, or use a large filter (efficient filter), then your r value (ratio of remaining waste per gallon) would change (remember that the RWI factor does not use r). Consequently, all that the chart indicates is a same-tank-to-same-tank comparison. For example, the RWI factor of a tank cleaned at 20% every seven days is the same as that same tank cleaned at 40% every two weeks. How much waste that amounts to, however, cannot be determined as r is unknown. Thus, my guidelines of 15 to 45 are just general guidelines. It is possible to have a RWI factor of 600+ if your tank is very clean (but most people could not achieve that low of an r factor, but my experience is that high RWI factors go hand-in-hand with negligence.
My spreadsheets, on the other hand, do calculate the r value and will allow users with a lot of plants to keep more fish than aquarists without plants or allow them to clean less often (some scenarios may allow more than a year between cleanings if r is low enough).
BTW, the mg/gal. was just used for the example. My spreadsheets use a biomass index based on the IFU number of all the fish in the tank as modified by the feeding schedule (heavy feeding will increase the estimated bioload per fish). I find that most average-stocked aquarium systems have about 7-15 IFUs per gallon.
Thanks, but I should mention that data changes every day in the aquarium world. Tomorrow someone could come up with something even better (and I would be happy about that).