How Much To Change?

[Mrseptember15]

How much water should I change in my 30gallon? Right now I'm doing 4gallons per week since my bio load is a bit on the heavy side.

[jdieck]

If you do proper supplementation of Calcium and Alkalinity and have means to export Nitrates and Phosphates and you have a good skimmer then the amount is OK toherwise adjust your change volume according to the reading of Nitrates. If more than 5ppm try increasing the volume you replace every week.