Water Changes

[biggin]

Okay, not sure where this should go but I will try it here....

A few times I have wondered if you do water changes a few times in a week or daily how much water you are actually changing. Does anyone have a calculation for this?

I saw this today http://www.fishtanks.net/#s9926 (http://www.fishtanks.net/#s9926) it seems to be about what I would have guessed.... if you changed 50% twice a week it would be about 75% of your total water changed....

Any thoughts?

[AndrewH]

Yeah, it's a percentages thing.

100% to start, change 50% which leaves 50%. Change 50% again, leaves 25% of the original and 75% new. But by the second and beyond, part of your original 50% new becomes old, make sense?

So the first go round would be 50% new and 50% old, the second go round you wouldn't have that same ratio, say maybe 40% new and 60% old (because some of the new you added last time is now old), so then you change 50% of that and you have 20% old and 80% new, the next time you change it you'll have dropped that a litte say 70% new and 30% old. So that would be 15% old and 85% new after a 50% WC.

[biggin]

Yeah, that is basically what I was thinking. I just saw the chart and was happy I was not the only one who had thought about it.

[rolloffhill]

:confuzeld::happydrunks:

[AndrewH]

(I can't see that "chart" anymore)

I don't think you can actually change out 100% without removing all of the water at the same time. Kinna the never get there by only going half math question.

[biggin]

I was thinking the same thing.... with the substrate always holding water and what not, and it would be pretty hard to figure out how much water you are actually changing.... I would think doing it daily that you change as much of the new as you do the old.... maybe I am wrong.

Stupid site... where did the chart go it does not look like they have updated it in the past 10 years....

[fishyjoe24]

:confuzeld::exactly:

[AndrewH]

Yeah, it'd be extremely hard to tell what's "old" and what's "new" a couple of day into it (doing WC everyday that is).

My personal opinion is that it's not needed, at least not that scale (50% everyday).

I am working on a system that will do a water change everyday, but by the time you get to the end of the week it'll have only changed out the same amount of water as a 20-25% weekly water change (which can be increased or decreased if needed).