Don't send them to bang...he doesn't check his email
J/K
FWIW
I used to subscribe to the no water change theory. I thought if the nitrates (and other tests) were low or undetectable then everything was OK. I had growth in my tanks and everything seemed and looked "fine". Now 15 years later (and some time ago) I realized that while color, growth and overall health can be maintained "exceptional" color, growth and health can only IME/O be achieved through and with water changes.
It can be difficult to change tried and true methods but one thing is certain...to test your system against something others have used with equal success all you need do is a regular water change for 6 consecutive months. One of two things will happen, either you will see an improvement or you won't. If you see no improvement after six months then you can discontinue the water changes and you have lost nothing. If you do see an improvement then it seems, you will again have lost nothing and perhaps even benefited...win, win.
Something else to perhaps consider is you seem to have completely torn down your system at least once when you moved and perhaps a large change and/or substantial maintenance when your refugium started leaking. You will again be moving and another mass cleaning will (?) occur. Since most systems IMO do not mature and fully stabilize until month 10-12 your tank (in the grand scheme of things) has had little chance to "prove" itself...no offense or flame intended.
, without a major event or change along the way. You may indeed have a complete closed ecosystem but without direct long term experience with another method it seems it would be difficult to draw an absolute conclusion to that effect. Sorry for the rant.
FWIW
Next month will be the 4-year anniversary of the 29-gallon tank in my office. It was set up to prove/show my co-workers that a saltwater fish tank is just as easy to keep as a freshwater fish tank. I have never done any maintenance (aside from cleaning the glass) of any kind. I intentionally neglect the tank I add water (sodium free distilled water) only when the rio on the BackPak sucks air and stops running, when the powerhead stopped working I unplugged it, when the powerfilter stopped working I unplugged it. When the heater came loose I just let it hang in the tank. I have 3/4" of "grunge" like material on the bottom and about 25lbs of live rock. The backpak stopped skimming long ago and now just circulates water through the media that came with it. The light bulbs work most of the time (now that’s bulb life for you) and overall the tank looks as neglected as it is.
There are two fish...a flame angel and a nox angle. Both are original to the tank (just under 4 years) their growth has been steady (slow but steady) I would guess that both are about fully grown at 3 1/2" I originally had 7 fish…all very small at the time it was my rainbow tank (red, yellow, orange, green blue, purple fish) In addition to the flame(substituted for red) and nox I had a purple pseudochromis (removed due to aggression), lemonpeel angel(sold to another hobbyist that couldn’t get a healthy one shipped in), a blue hippo tang(still alive and well in 125 gallon tank), and a green coris wrasse (returned to LFS when he outgrew the tank)
The water is clear and not yellow even when checked in a white cup. There is no trace of ammonia or nitrite and depending on what kind of flake food I use a get the occasional cyno bloom from phosphates. There are no other nuisance algae growing in the tank as well as no macros. The tank has never seen an illness ich or other. The one thing that has climbed off the chart is NITRATES. I suspect that they are well in excess of 130+ppm. About a year ago they were right at 100ppm and I have no reason to think they have done anything but climb.
Bottom line is that with supplemental filtration and water changes I am confident I could bring the tank back down to "acceptable" levels but that isn't the point. I have not added livestock for fear of further raising the bioload and more importantly I do not believe many if any other fish could/would survive. Next month at the end of year four I intend to tear the tank down (my point being made to everyone in the office) and reset the tank for the next experiment COLD WATER
but that is another post.
Can a tank be run without water changes...YES but in my experience and opinion it is not a good idea IF you want to enjoy the "BEST" a saltwater tank has to offer.
Regards,
SiF
PS pictures available upon request