Very cool. It is tempting to try out the no-water-change for this time-pressed reefer. Wondering what kinds of corals you are keeping and whether they are doing well, and what your maintenance routine is? There are several essential elements that are very rare (selenium, molybdenum, copper, probably manganese listed above, and others), which are at concentrations that are likely below the accurate detection limit of the ICP method. These unknowable rare elements (plus the unknowable toxins, plus inevitable salt imbalances caused by 2-part) are the reasons I do water changes. Just wondering what you think about these things, and whether you have maintenance or supplements that might address them.