I thought that it was about time that I made any blog readers aware of a utility that Spider from Uaru-Forum created to calculate percentage water changes.

This is an extremely useful utility if, like me, you always empty the same amount of water before replacing with fresh. It is also essential to know, if medication or salt are being used, exactly how much of the original still remains.

Let us say that you have a 100 litre tank and you take out 20 litres and replace this with fresh water. This represents a 20% water change and 80% of the original is left. Repeat this procedure and you will have carried out a 36% water change with 64% of the original remaining. A third time gives a 48.8% change with 51.2% of the original remaining.

This is, of course, due to the fact that during your subsequent water changes you are not only removing 'old' water, but also water from the previous changes.

The calculator is found by clicking on the following link:-

Uaru-Forum Water Change Calculator

Hope that you find it as useful as I do!

Let me know if any further explanation is required.