Water Changes in the Reef - Reefs.org

[Reefie]

The Tables got lost in the copy & paste, below is the link also.
http://www.reefs.org/library/article...html#phosphate

Water Changes in the Reef Aquarium - Data

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By Troy Brightbill
Figure 1: Tables of nitrate concentrations.


Using 5% water changes to remove nitrateChange # mg/L NO3 Change # mg/L NO3 0 20.0 14 9.8 1 19.0 15 9.3 2 18.1 16 8.8 3 17.1 17 8.4 4 16.3 18 7.9 5 15.5 19 7.5 6 14.7 20 7.2 7 14.0 21 6.8 8 13.3 22 6.5 9 12.6 23 6.1 10 12.0 24 5.8 11 11.4 25 5.5 12 10.8 26 5.3 13 10.3 27 5.0
Using 10% water changes to remove nitrateChange # mg/L NO3 Change # mg/L NO3 0 20.0 8 8.6 1 18.0 9 7.7 2 16.2 10 7.0 3 14.6 11 6.3 4 13.1 12 5.7 5 11.8 13 5.1 6 10.6 14 4.6 7 9.6
Using 15% water changes to remove nitrateChange # mg/L NO3 Change # mg/L NO3 0 20.0 5 8.9 1 17.0 6 7.5 2 14.5 7 6.4 3 12.3 8 5.4 4 10.4 9 4.6
Using 20% water changes to remove nitrate Change # mg/L NO3 Change # mg/L NO3 0 20.0 4 8.2 1 16.0 5 6.6 2 12.8 6 5.2 3 10.2 7 4.2
Using 25% water changes to remove nitrate Change # mg/L NO3 Change # mg/L NO3 0 20.0 3 8.4 1 15.0 4 6.3 2 11.3 5 4.7
Using 50% water changes to remove nitrateChange # mg/L NO3 Change # mg/L NO3 0 20.0 2 5.0 1 10.0
These tables simply show how long it would take to lower nitrate levels, assuming no further nitrate build up, by using water changes of the given percentages.
Figure 2: Nitrate levels graph.


To find out how long it would take to lower your nitrate level by using water changes, assuming no further build up of nitrate, simply find your current nitrate level on any of the three plots. Follow a plot to the target level to find the number of changes required.
Figure 3: Phosphate levels graph.




Using this graph, one can find their current phosphate level and determine how long it would take to lower it to a target level, using any of the three plots shown. For instance, if you wish to lower your phosphate from 1mg/L to 0.2mg/L using 10% water changes, find where the 10% line crosses the 1mg/L line. This would be approximately 7 on the x-axis. Follow the line until the phosphate concentration is 0.2mg/L, which would be 22 on the x-axis. Subtracting 7 from 22 gives a figure of 15 water changes required to lower phosphate from 1mg/L to 0.2mg/L using 10% water changes.
Figure 4: Calcium levels graph.


This graph assumes a theoretical calcium consumption rate of 10.6mg/L per day. The graph does not take into account any possible chemical reactions that may occur with such depleted calcium levels. This graph is designed to show how calcium will become depleted without using calcium supplements, in a 55 gallon system with a calcification rate of 4kg/m 2 per year. Water changes are signified by the spike seen every seventh day on the graph.
Figure 5: Magnesium levels graph


This graph shows how long it takes to replenish magnesium by only using water changes. To determine how long it would take to correct your magnesium level by using only water changes, find your current level on any of the three plots, and follow it to your target level.