WHY is useful to understand on general principles...for one thing because 'we just do it this way' is sloppy thinking, and for another because in an emergency you may have to take a radical decision against the grain and knowing WHY you do things is valuable information.
A big why.
Why do we cycle?
Basically because changing filters is a pita, and because corals do best if you don't make radical periodic changes.
You don't need a cycled tank to keep marine critters alive.
You do need a cycled tank so the system doesn't have spikes of clean versus not, so it doesn't build up waste, then lose it all, and so that critters that need a very stable chemistry can thrive. Cycling doesn't do a THING for the water the critters are in...except assure that the water chemistry does not bounce up and down like a yoyo. So yes, if you want to change the water daily, cool, and your fish will probably be fine. Your corals will probably not grow.
Fish can tolerate this, which is why fish-onlies can get by with a canister and corals may have trouble.
What does a skimmer do?
It gets amino acids out and keeps the water 'nicer'. Softies and lps tolerate 'richer' water than sps, which wants crystal clear water. Don't panic if your skimmer goes down for a few days---unless you have sps. But do get it back in operation, because it's sort of the toilet of your tank, and sooner or later---you need to flush.
What does acclimation do?
Mostly it protects fish against osmotic shock: if your internal tissues are bathed in water of a different salinity than the rest of your body, kidney cells can explode from the pressure difference (high vs low salinity) leading to death within about 3 days from uremic (kidney failure) poisoning. Because of the way osmotic shock works, it's pretty safe if the new water is LOWER than the water the critter was in---but HIGHER salinity will kill.
You can raise the salinity on critters about .002 every five minutes---but if the critter is delicate, or you just don't have room for an elaborate setup, set your qt tank at the same salinity as the shipper puts in the shipping bags. Phone and ask them. Then don't acclimate, just test the water to be sure you're ok (a .002 jump upward is usually safe) and put the fish right on in. Raise the salinity gradually, by natural evaporation, and the fish never suffers a moment of kidney stress.
SECOND caution about acclimation: leave a fish in a shipping bag more than 30 minutes and they may die within 3 days from another kind of kidney damage: AMMONIA. Respiration and excretion in the bag during transit build up ammonium, and co2. The instant you open that bag, a clock starts ticking: the release of co2 from the bag causes a ph change which immediately starts ammonium converting to its lethal evil twin, ammonia. Your fish can DIE of too much caution. A product like Prime or Amquel can stop that process and neutralize the ammonia, but all in all, it's a good idea to have that qt adjusted to welcome the newcomer, just float him WITH BAG CLOSED for 15 minutes to equalize the temperatures, open the bag, test with refractometer to confirm the salinity match, then put him straight across with NO dripping unless you find a greater than .002 mismatch. Over-long acclimation kills. Period. Your fish that has only come from the fish store is much safer---but a shipped fish has had a lengthy time to build up ammonium in that bag. Got it?
There are WHYS for what we do and don't. Feel free to ask. Sometimes it's just convenience or easiest. More often---there's a much more critical reason.
A big why.
Why do we cycle?
Basically because changing filters is a pita, and because corals do best if you don't make radical periodic changes.
You don't need a cycled tank to keep marine critters alive.
You do need a cycled tank so the system doesn't have spikes of clean versus not, so it doesn't build up waste, then lose it all, and so that critters that need a very stable chemistry can thrive. Cycling doesn't do a THING for the water the critters are in...except assure that the water chemistry does not bounce up and down like a yoyo. So yes, if you want to change the water daily, cool, and your fish will probably be fine. Your corals will probably not grow.
Fish can tolerate this, which is why fish-onlies can get by with a canister and corals may have trouble.
What does a skimmer do?
It gets amino acids out and keeps the water 'nicer'. Softies and lps tolerate 'richer' water than sps, which wants crystal clear water. Don't panic if your skimmer goes down for a few days---unless you have sps. But do get it back in operation, because it's sort of the toilet of your tank, and sooner or later---you need to flush.
What does acclimation do?
Mostly it protects fish against osmotic shock: if your internal tissues are bathed in water of a different salinity than the rest of your body, kidney cells can explode from the pressure difference (high vs low salinity) leading to death within about 3 days from uremic (kidney failure) poisoning. Because of the way osmotic shock works, it's pretty safe if the new water is LOWER than the water the critter was in---but HIGHER salinity will kill.
You can raise the salinity on critters about .002 every five minutes---but if the critter is delicate, or you just don't have room for an elaborate setup, set your qt tank at the same salinity as the shipper puts in the shipping bags. Phone and ask them. Then don't acclimate, just test the water to be sure you're ok (a .002 jump upward is usually safe) and put the fish right on in. Raise the salinity gradually, by natural evaporation, and the fish never suffers a moment of kidney stress.
SECOND caution about acclimation: leave a fish in a shipping bag more than 30 minutes and they may die within 3 days from another kind of kidney damage: AMMONIA. Respiration and excretion in the bag during transit build up ammonium, and co2. The instant you open that bag, a clock starts ticking: the release of co2 from the bag causes a ph change which immediately starts ammonium converting to its lethal evil twin, ammonia. Your fish can DIE of too much caution. A product like Prime or Amquel can stop that process and neutralize the ammonia, but all in all, it's a good idea to have that qt adjusted to welcome the newcomer, just float him WITH BAG CLOSED for 15 minutes to equalize the temperatures, open the bag, test with refractometer to confirm the salinity match, then put him straight across with NO dripping unless you find a greater than .002 mismatch. Over-long acclimation kills. Period. Your fish that has only come from the fish store is much safer---but a shipped fish has had a lengthy time to build up ammonium in that bag. Got it?
There are WHYS for what we do and don't. Feel free to ask. Sometimes it's just convenience or easiest. More often---there's a much more critical reason.
