all new water. so far the summary is perfect pls take pics so we can use it in our thread to track patterns. we are shaking the rock about in water, it can even be drawn off tank water. its just to eject any pent up waste from the pores on the bottom-sitting parts etc.
its handy to know that if you move all that live rock into the sump its a skip cycle setup, hard to imagine I know. we're basically ripping out/replacing or washing all the sand and it just doesnt matter, for pages we rip out sandbeds and not even put them back in the sand rinse thread. the rock has to instantly take over, and we're not losing animals which is how we're measuring success.
Even though its a long thread i recommend reading the specific jobs to see patterns that stand out, its worth it since this is your $ on the line. the summary above is reliable though, that you arent reducing the live rock at all is why its a skip cycle like how they set up all those reefs at a MACNA convention, or how we're moving reefs among homes without losses.
That much sand could be 4 hours rinse

make it clean, use tap water like we do so you can rinse rinse x400