It's just above the thick line.:mrgreen:

salinity
 

i run mine at 1.025 and no troubles yet, my only problem is trimming all the time!

1.025 - 1.026 is were mines at as well.

1.24-1.25 is where I keep mine.

maybe its be cause us newbies dont buy books we just talk to the LFS and they always suggest using a hydrometer and that has indication marks of 1.020-1.024 thats what i was told when i first started

Bahahahahahaha!!! Point made! Good one Brad. :mrgreen:

Natural Seawater average is 1.0264

Also the higher your salinity the better your skimmer works.

Could it be the confusion with hydrometers that were not calibrated to the proper temperature?

Martin Moe in the Marine Aquarium Handbook says that a hydrometer calibrated to 59 degrees will give a reading of 1.022 at 80 degrees, when the true reading should be 1.026.
John Tullock in Natural Reef Aquariums says in a chart one part of his book that the recommended level is 1.022-1.024 (page 119). In another part he explains a bit further, saying that "A typical glass hydrometer reading should be 1.022-1.024 at 75 degrees F" (page 67) but then tries to explain how temperature affects reading. He also says that seawater is 35ppt which "corresponds to an observed hydrometer reading of 1.024 at a tempurature of 75 degrees" (page 121) - No mention of whether or not that hydrometer is calibrated to 59 degrees or 75 degrees.

Confusing.

Anyway, tullock also says "Marine Aquariums are often maintained at a lower specific gravity in the belief that the lowered salinity reduces stress on fishes and makes the survival of parasites less likely. I am aware of no evidence to support this practice" (page 121)

I seem to recall the reason being that the lower salinity made it easier on the fish because they didn't have to work as hard to offset the loss of water from their bodies because of osmosis.

I keep mine at 1.024 at a water temerature of 78, read with a hydrometer calibrated to 75 - whatever that means.

I also keep mine at 1.024... I was a big believer of 1.025-1.026, and for almost 3 years of having my big tank, 1.026 is what I kept it at. But with the troubles I have had with SPS during the summer, and with some research, I have found that in nature many corals/fish are in the 1.023 - 1.025 range (liveaquaria.com also shows these ranges). So I decided to go in the middle at 1.024, and have had it at this reading for about a month or so now. Things seem just fine for coral and fish. So i am thinking the higher salinity isn't necessary.

I don't care about salt cost, and I am not on a budget... so price isn't an issue, I just want a healthy environment.

For those that can give reason why the higher salinity is better, please let me know why. I am more than happy to change it up again, but without just cause, I just don't see why I should anymore.

I keep mine at 1.026, simply because an undiluted reef is that value. I don't have any reason to say 1.024 is bad, other than it lowers other values (Ca, alk the big ones) at which point we then artificially raise the levels. I find it hard to believe it's stressful on the fish, as that is what their normal environment is (for reef fish). Local sea water is much lower, but I don't keep local species.
SPS thrive in the wild, at 1.026, and that value matches other things we don't measure (trace elements). Lowering salt lowers other values that may (or may not) be important, so without knowing for sure, I'll err on the side of where the livestock came from. I think, if anything, an unnaturally low level might introduce stress.