Water Change Calculation

[MarinaClown]

Hi,

I have a standard 40G breeder reef tank. However, it fits about 32-33 gallons of saltwater due to live rock and sand. For purposes of calculating the percentage of weekly partial water change is it more appropriate to calculate it based on the Size of the tank or the volume that's in the tank?

 

[jeffaquarius]

Volume accuracy for partial water change is not that critical. The more the better. A 5 gal is fair enough which is a little more than 10%.

 

[MarinaClown]

Volume accuracy for partial water change is not that critical. The more the better. A 5 gal is fair enough which is a little more than 10%.

Thanks. About to do a 10 gallon water change. Depending how one looks at it, it will be either 25% or almost 30% water change. The difference seems to be insignificant.