anyone used the water change calc

[relaxednature]

Im not sure what this calc is telling me..

Week % Pure % Non-Pure PG NPG RNPG

1 14% 86% 14 86 14
2 26% 74% 26 74 12
3 36% 64% 36.4 63.6 10.4
4 45% 55% 45.3 54.7 8.9
5 53% 47% 53 47 7.7
6 60% 40% 59.6 40.4 6.6
7 65% 35% 65.3 34.7 5.7
8 70% 30% 70.2 29.8 4.9
9 74% 26% 74.4 25.6 4.2
10 78% 22% 78 22 3.6
11 81% 19% 81.1 18.9 3.1
12 84% 16% 83.7 16.3 2.6
13 86% 14% 86 14 2.3
14 88% 12% 88 12 2
15 90% 10% 89.7 10.3 1.7
16 91% 9% 91.1 8.9 1.4

what does the % pure and PG, NPG and RNPG mean exactly?

anyone know?

Thanks

 

[aztbs]

It is saying that after 16 weeks, that 91.8% of the water in the tank will be "new water" from changes and 9% will be "original" tank water.

Here's a thread from the creator, I think it will make more sense:
http://www.reefcentral.com/forums/showthread.php?s=&threadid=522030

 

[aztbs]

pg - "pure" gallons
npg - "not pure" gallons
rnpg - replaced non pure gallons

It just shows that each time you do a water change, that you remove less and less of the "original" volume of water.

 

[relaxednature]

oh I see.. ok thanks.