This tool can help you figure the effect of water changes on the quality of the water in your tank.
The word "dirt" here is used to describe any kind of substance dissolved in the water. This may be: Nitrate, Fertilizers or any other element of the water you can measure it's concentration.

To use this tool: Fill in the required fields that best fit your aquarium:

• Initial amount of "dirt": The initial concentration of the element (for example, right now).
• Daily addition of "dirt": How much of the element is added each day? (for example fish waste or fertilizing).
• I change the water every: How often you make a water change?.
• The amount of water changed: In your water changes, what percent of the water do you change?
• The amount of dirt in the added water: If you add pure water this should be 0. If the water you add contains the element - what is it's concentration?
  

Inside the blue circle you will see the amount of "dirt" that will remain in your tank after the specified number of days.
You will also see a graph representing daily concentrations of the dirt.