When to top off with saltwater vs plain RO?

[keithadaniels]

I'm a newbie so please be gentle I know that I'm supposed to use plain RO water when topping off evaporated water. But I am going to be getting some new coral this weekend and between the acclimation and dipping processes I will probably be removing about 2-3 gallons of water from my tank. I have a 29G Biocube that with the LR and actually water capacity is probably about 22G of actual water. So if I'm removing about 10%-15% water or 2-3 gallons should I replace the tank water with saltwater or plain RO? Is there a percentage cutoff where saltwater should be replaced vs plain RO?

Thanks.

 

[KatyKat]

Ive always based mine off of the salinty readings. If the salinty is low i add saltwater, if its good or high, i add ro water

 

[huma-huma]

general rule of thumb should be if you are PHYSICALLY removing water, replace it with saltwater, the only time you should be replacing with ro/rodi water is for evap. nothing else.

obviously you need to keep the SG in check so you'd want to add/remove sw to keep it stable