water change

[madlynb]

I have a 125 gal salwater tank w/40 gal long sump, skimmer, refuge, 2 OT, live rock, 3" live sand bed and fish.
I want to perform a water change. Can you please advise as to how much to change. Do I remove the water from DT or sump? When adding water do I use mixed saltwater or plain RODI water?:question:

 

[Bifferwine]

When doing a water change, where you remove saltwater, you need to replace it with saltwater. To compensate for evaporation (you know how your water level seems to get a bit lower every day), you need to use plain RODI water. When water evaporates, it leaves the salt behind.

You should change 10 to 20% of your tank's volume once a week or every other week. So for you, it would be ideal to change 12 to 24 gallons 2 or 4 times a month. Whether you want to remove it from the sump or display tank is up to you. For my tank, I find it much easier to remove it from the sump because that way I can leave all the powerheads running in my main tank, and it's easier to tell the level I need to drain from the sump.

 

[mblack]

I personally change 10% per week, others may do more or less. If you were to do the same then you would change around 16-17 gallon. To do this use mixed saltwater that is the same salinity as your tank. Also heat the water to the same temperature. It is best to mix the saltwater at night and leave it heated overnight with a powerhead to get some air into the water and to make sure it is properly mixed. Don't think it matters if you do it from the sump or not, I don't have one so don't know, someone else will be able to advise on that.

Only use plain RO/DI water for topping up evaporated water.

HTH

Matt

 

[yote]

When I do a change on my 125,Its usually about 15 gallons.Sometimes I'll drain it from the sump,sometimes I'll drain the display and siphon the rocks off.Just depends on what kinda mood I'm in at the time.