Hi,
Everyone does indeed have their own way to do things.
A tank setup under 1 year is going through all kinds of changes. Things are not balanced and get out of hand easy. Water changes are the best way to keep the water parameters on track. As the tank ages, the living organisms of algae, tiny sponges, bi-valves (filter feeders)...along with the tiny critters in the rock, settle down and the tank kind of takes care of itself. Everything balances out, and you have a little wiggle room if you get lazy with water changes. (not so with nano tanks, there is never wiggle room with a small tank)
Nitrates are not a big concern with fish, but inverts will have problems and die if they get over 40. I ways made sure to not let NO3 (nitrates) get above 20. Phosphates are the enemy. I keep macroalgae now, and nitrates (NO3) and phosphates (PO4) are a happy 0.
In the coal mines, miners would keep a caged canary with them, and if the bird showed stress then they knew the air was bad. In a SW fish tank, the shrimps do the same thing as the canary. They are the first to die if the water quality goes toxic. LOL...that little trick won't help if you keep fish that eat shrimp.
The more often you do the water changes, the less you have to swap. I always did a 3% change, if I only did changes once a month. So on my 90g I would swap 30g. Now with the 24g sump and the 18g refugium, I have approx 130g (the sump is not full). So 40g should be my regular water change amount.... When I did daily changes (API test kit was off, so I thought something was wrong when it wasn't) I changed about 3 to 5 gallons a day.
thanks anyway
