ADDED: Aww... the pictures were all resized and screwed up on Photobucket... the excel sheet is attached (only change values in the highlighted cells)...So I was bored in a meeting today so I built a spreadsheet. I figured this thread was as good as any of the other 5 water change threads to resurect. I am now convinced that I do want to do tiny daily water changes in my new setup. The really intresting thing about seeing the spreadsheet i built is that you normally only see the calculation out to about 10 waterchanges (the sheet has 1/2 years projection). After a month or so (depending on build up, WC rate, etc) you actually reach a horizontail asymtope on the levels. I have a few cases shown below:
*note* The Weekly Water Change Rate (WWCR) is given to the spreadsheet and it divided by 7 to get the daily rate. Also, The setup starts the daily water change on day1 but the first weekly water change is on day7
1A. Nitrate - Assumeing a 0.1 PPM per day buildup (someone with wetdry and no natural nitrate reduction method), 20% weekly waterchange, starting nirtrate level of 5 PPM
1B. Nitrate - Assumeing a 0.1 PPM per day buildup (someone with wetdry and no natural nitrate reduction method), 50% weekly waterchange, starting nirtrate level of 5 PPM
As you can see. It doesnt really matter if you change daily or weekly you are approximatly at the same level. Changing weekly will remove more that is just accumulated over the course of the next week until the next water change. You can also see that the maintained level is based on your WWCR
2A. Calcium - Assumeing Absorbsoin of 20PPM per day (SPS tank), 20% WWCR, starting at 400 PPM
2B. Calcium - Assumeing Absorbsoin of 20PPM per day (SPS tank), 50% WWCR, starting at 400 PPM
You can see that even a 50% water change weekly wont keep up your Calium levels with this load
3A. This is the case for any generic toxin or "chemical warfare" unleashed by coral, 75 Gallon Tank, PPMs are notional
3B. This is would be the same case except with an additional 75G sump. The same livestock exisits in the tank so with double the water volume, they only produce half the PPM per day (they arent going to double their toxin output) This shows that you can still remove the same VOLUME of water you did in 3A. Notice the %WWCR is differnt but gallons is the same
So if you add a sump it looks like there is no need to double your WWCR just to meet some magic Percentage. All the numbers were made up so dont say they are impossible
they just prove a concept.
Of course I am not advocating changing less water or less often...Why would you listen to me Im just a guy that knows how to play with Excel, anyone see any major flaws in this theory?