specific gravity

[ericosuave]

what is a good specific gravity number? according to the coralife DEEP SIX I am at 1.026.. I need to add about 2 gallons of fresh water to top off and it might lower it to like 1.023.. or 1.024.. is this fine? what is the number i should not go below, and what is the number I should not go above?

My tank consists of a true perc clown, hammer coral, candy coral, and a piece of acro

 

[lando]

1.026 is a bit high. Most here suggest running a reef between 1.023 and 1.025. Just be careful with the "arm" style of tester. They are not very accurate and can often times have small bubbles on the arm that will cause a false high reading.

 

[Phyl]

Worse than the bubble (or at least just as bad) is the fact that a lot of the time they seem to read .004 lower than your salinity really is (mine was reading 1.023 when refractometer said 1.027). My goal is 1.024 now that I'm measuring with a reliable device. With a swing arm I'd probably resort to middle of the road hoping that at the end of the day I'm almost within range.

 

[ericosuave]

ok thank you very much!

 

[rayjay]

Nothing wrong with 1.026, which is what most reefs are considered to have.
Ideally, the plastic hydrometers should be checked against a refractometer or at least against a certified hydrometer. Then be sure it stays accurate by cleaning it overnight in white vinegar at least once a week. Rinse in fresh water after each use.

 

[Jonathan G.]

also the new instant ocean ones if used correctly, dip it in the water til the water rises from the side- dont let the water from the aquarium drip into the top of the hydrometer and it will fill up slowly and will give you a better ready and not have to worry about bubbles. but definitly not as good as a refractometer and has to be cleaned regularly.