I totally agree that PH
monitoring is an exellent indicator for water changes (fresh and salt), and low PH
(below8.0) is perhaps the single biggest problem causer in a marine tank that most people don't pay attention to. High nitrates being next on the list. Low PH
will promote nuisance algae, stress if not kill corals and inverts, cause calcium/hardness levels to bounce all over the place, and generally reduce the health of the tank.
However, I'm not sure what's worse. Constant water changes from a tap, or just letting the tank turn into Amazon basin. The more water changes you do means you dump more tap water contaminants into your tank, which then means buying an RO
unit to fix the problem you created by trying to fix another problem.
I think I see the same dilema with Clownfish that I had to come to terms with before starting up my reef tanks again. Basically, I *hate* doing water changes and will procrastinate as much as I can until my maroon clown starts writing 'idiot human' backwards on the algae on the glass to get my attention. It's comes down to a choice; either replace water in the tank to replenish nutrients and dilute bad things, or take better care of the water that's in there.
I choose the later, and drastically reduced the need for water changes with aggresive skimming and good old calcium buffers. My own preference for the later is Aragamilk, and adding half a cap every third day keeps my PH
locked down tight at 8.2-8.3 and coralline algae and soft corals growing at a near nuisance rate.