vitz
New member
although I believe in water changes I would have to think the only reason we don't see more "anomalies" of people not doing water changes is because it isn't the norm.
we are taught from the get go that we need to do water changes.
i would be interested in hearing from people who have been in reef keeping for 20 or so plus years. key word being reef, and not saltwater fish.
my first reef tank was in 1977-ish. (i hope that qualifies ;-p )
it's my personal opinion that anyone who advocates the superiority of a totally closed system over a 'semi-closed' one is someone w/no real world experience on any appreciable scale to be able to make any statements about the merits of one over the other

as an example:
all fish produce an 'anti growth' hormone as part of their biological arsenal to foster the development of the first biggest growing fishes over the 'runners up. it's why fry grow in 'spurts' of a sort (e.g.-remove the 10 biggest fry, and some of the smaller fry will then 'spurt' in growth). when doing wc's, you get alot more fry 'spurting' constantly as a percentage of the whole population.

there are many other hormones that fish release into the water throughout their life, that we can't measure. that's but one very tiny example of a class of organic compounds where we don't know if they're 'sinkable' or not. to say nothing of the probable thousands of compounds produced by corals/inverts-some of which we've discovered, and some of which we know are HIGHLY toxic to other corals/inverts.
i wouldn't take a risk of a probable waste product POSSIBLY rising ad infinitum, and not knowing what the effects MIGHT be,when there's a profoundly simple way of eliminating that as a variable.

it's about doing what's most prudent, and 'covering one's butt', given our present knowledge base of what's going on.
eliminating variables and unknowns in a closed/semi-closed system is fundamentally one of the most important concepts/practices of disease prevention and control of any animal husbandry in a closed/semi closed system.
on the whole, it's been my direct experience that wc's are a preferable way to go, and nothing substitutes for something so simple that provides as much benefit all around. (assuming, of course, that the water being used has the proper parameters/quality needed, natch - this doesn't mean that various dosing and 'artificial sinking' isn't useful or improper-the best success is achieved using BOTH methodologies, together, ime/imo).
my healthiest most productive reef tank got a 90% (!) wc every week to two weeks. (w/ properly aged/mixed/adjusted sw).
constant damsel spawning, and phenomenal coral growth, in spite of keeping large leathers w/ large lps's in a relatively small (75gal) tank, along w/ nightly plankton/zooplankton/copepod/gammarid 'population explosions/blooms'. there was also dosing and skimming going on-but the tank ALWAYS looked it's best following a large wc.
i've yet to see non wc systems, as a whole, come close to wc'd systems, w/ regards to polyp expansion and overall system health (including the fish). not saying there aren't any, or that it can't be done, but wc's definitely make it easier to obtain that objective, by and large.
this is the conclusion i've come to after working w/ many different size systems-from 2.5 gallon guppy tanks, to commercial hatcheries (fw) to lfs's, and large closed system husbandry on the wholesale/import side of things.
hth
