how much water for a water change?

[Europhyllia]

I change 10 gallons every week.
I think with the tank (125g tank) and the sump (50g) I have about 125g of actual water (not rock/sand/etc.) so that would amount to weekly changes of about 8%, right?

[timmytimtim]

I have a 75 gallon and change 20 gallons every week. Everything seems to be much happier that way.

[GoneReefing]

For myself I have been doing weekly changes on both tanks
8 gallons for my 75 and 2 gallons on the 20.

Roughly 10%/week. On a week that if I skip which is very rare, I will do a 20% the following week.

[Paul28]

what ive noticed is the older my tank gets the less waterchanges i half to do still keeps clean clear water

[cowboy572]

I agree less water changes are better. I do a 12 gallon change on my 110 tall every two weeks.

[firecoral3msd]

Roughly 10%/week.

I have always found this percentage to be the best, but that is my opinion.

[kkiel02]

On the 180 I have been doing weekly 10 gallon changes. I havent really seen a need to do anymore at this point. Every so often Ill do a 15 gallon if I feel like it but so far so good.