Specific Gravity

orucco

Member
Hello, I am new to saltwater as everything has changed in 20 years. I have learned a lot from this forum and am very grateful. I now have a 75 gal. glass tank slowly filling with water from a RO/DI unit, which I learned about here. I have Red Sea Salt that states 1 level cup equals 3.75 gals - 1.021. I have an instruction sheet from a LFS that is all marine and reef that recommends 1.019 for fish - 76 - 78 degrees and 1.022 - 1.024 for reef - 76. I am looking at buying online 50lbs of fiji lr and it recommended 1.023 - 1.024. This will be a fowlr to begin with and maybe later on try to maintain some of the easier corals, so what would be the recommended specific gravity and temperature to start with. Sorry for the long post but I searched and could not find the answer..........Thanks again for all the great info.
 

squidd

Active Member
Long story and lots of explaining...(do a search on "refractometer" or "salinity")...
Short version...Get a refractometer and set salinity at 35 ppt...:yes:
Start with temp around 78-80...and you can "fine tune" from there...
 

lion_crazz

Active Member
Definitely go and buy a refractometer before you put any fish in the tank. This device, priced at $60, will allow you to monitor your specific gravity at perfect accuracy and is 10 times superior to any other product.
The temperature of the tank should be about 78 to 80 degrees. More importantly, you want stability rather than anything. Set it to one temp and leave it there.
Lastly, a good specific gravity for fish is 1.021. Live rock does not need a specific level to be kept healthy. Like temperature, specific gravity needs to be very stable for the fish too.
 
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