Originally Posted by
bswe22
http:///forum/post/3179918
I have been told that you do not really need one unless you are planning on having a reef tank with lots of difficult corals in it.
I tend to disagree with that. fish are quite sensitive to swings in specific gravity, it takes more energy to osmoregulate at higher specific gravities, it also takes energy for a fish to accomodate swings in SG, so by using innacurate equipment your adding stress to your fish. corals are actually not very sensitave to swings in SG at all. as long as its above 1.024 it can go from 1.024 to 1.027 in seconds and a coral wont even cringe. a fish expiriencing the same thing would have a very good chance of dying by being unable to adjust its osmoregulatory process fast enough, or at best being stressed out making its immune system weaker thus encouraging disease.
its the motile invertabretes and fish that tend to be killed by sudden shifts in osmoregulation brought on by shifts in SG. especially echinoderms (sea stars)