Since water change is one of the most important husbandry of reef tank maintenance , one consideration that we had was to make the water change process extremely hassle free.
as the house is rebuilt, we were able to install a drainage system right under the tank cabinet. This drainage pipe is estimated at a height to drain about 15-20% of the tank volume, an optimum amount for water change. It is controlled by a ball valve, once open, the water will flow down to the drainage as shown in e picture below.the RODI waste water tube is also connected to the drainage pipe! And yes the RODI is installed within the cabinet!
this 5 stage RODI is powered by a booster pump and fills about 60-80 liters per hour! And it fills this built in mixer tank that can hold more than 20%.
we installed a return pump and fixed a two way pipe to 1) mix the salt using the return pump circulation and 2) pump the water up back into display tank.
so water change is just, drain the water with the drainage pipe, pour the salt into mixer tank, switch the valves to pump the water up to display tank. There you go, a water change process without pails!
haha, love to hear your comments on this!