I am converting my tank from fresh to brackish and will soon move to full salt. I have mostly monos and one columbian shark. I am using the regular Instant Ocean salt mix. Does anyone know how many cups of salt it takes to get SG 1.025? The bag says it takes something like 1.5 pounds, but I dont have a weight scale that will measure that. I am testing the salt levels, but I still have not figured out the exact measurment.

I have been slowly adding buckets of salt water to my aquarium when I conduct water changes. My SG seems to fluctuate though. I added 10 gallons and tested my aquarium 24 hours later. The SG read 1.007. Today, another 24 hours later it read 1.0035. I had this problem a couple of weeks ago. I added salt water and after about 12 hours the SG was 1.005 and two weeks later the SG was 1.000!!!! Is this normal? I am using an expensive refractometer that I bought and it is much more accurate than a standard hydrometer. My only thought is that the cultured/cast prefabricated stone I have in my tank is absorbing the salt. Is it this, or does it take days for the salt to completely dissolve? What do you guys think?

i can definatley take days to completely disolve - - -are you pre mixing your salt water a day or two in advance or "hot" mixing it {mixing and adding it within like an hour or two} so the gain oer a day or two is normal {kinda} but the drop is interesting............if your rock is "absorbing" the salt you should be seeing salt creep or deposits of some sort on them

as far as how much to mix to make a 1.025.........of course that depends on the volume of water - - - when i was useing instant ocean is was about 1/2 cup per gallon - - -but again ....if you premix a couple day ahead of time you can adjust it before you need to add it

Boss