Help with Specific Gravity

[alyssamavon]

Hi. The Green Spotted Puffer fish I have came from a freshwater tank. I know that GSP are brackish to marine, so I obviously want to acclimate it from freshwater. The GSP is a juvenile and from what I've read, they should be acclimated to 1.005-8 SG, and that the SG should be raised by only .002 a week.

So, my question is, how do I figure out how much salt to put my tank to .002 SG, when all of the hydrometers I have found start at 1.000?
My tank is 30 gallons.
If anyone could help me with this, it would be greatly appreciated!

-Alyssa

[geronimo69]

Sorry. but I had to LOL a little bit here...

You want the gravity to be at 1.002

Hydros and refractos (ones I've seen) all start at that level. Full marine is 1.024-1.026

I'm sure RTR will explain why they start at 1.000.... just wait...

[Flutter]

Everything is 1.0XX. So, you actually want to raise your salinity to 1.002 and you increase it by 0.002 max per week. For example, if your tank is at 1.000 and you want to raise it to 1.002 then you should do a 50% water change and the new water should be at 1.004. Once you add that it will be divided in half and your tank water will be at 1.002

It looks like you just had the numbers switched around, does it make more sense to you now?

PS: Eventually you'll want the SG to be above 1.008, the levels that you mentioned sound more like they're for a F8.

[alyssamavon]

thanks everyone! i get it now.

[RTR]

Fresh water is theoretically 1.000, so if an instrument measure below that, the solution is not pure water or the instrument is incorrect. Ultrapure water is a laboratory material only, it is not found in nature. Even rain and fog are not pure water - things from the air dissolve in the condensing water droplets.

Dissolved minerals increase the specific gravity of the water, so we read numbers higher than1.000 depending on the amount of total dissolved minerals.

Seawater is a highly complex solution, and world-wide is remarkably stable. Purely for convenience in talking about it, hobbyists break the varied levels of salt water/seawater down into three crude categories - low-level brackish (~1.001 - 1.008); mid-level brackish (1.009 -1.016); high-level brackish to high density seawater (1.017 to 1.025). This three-way split is also handy because the bacteria involved in nitrification (always important in captivity) also change at or a bit above the break between low-level BW (brackish water) and mid-level BW. We also use different techniques in high-level BW and SW (seawater or salt water). The SW effective techniques an equipment will not function well at all below 1.016 -1.018, and work best at and above 1.020-1.021.

Pragmatically we have found that certain BW puffers need some level of BW which may be optimum for their health and long life, and in such water they can reach or exceed maximum observed wild size, and average lifespans at some multiple of that seen in the wild. That level varies from species to species. The F-8 appears to need 1.003-1.005 specific gravity for optimum health an lifespan. The GSP requires higher levels of dissolved salts, apparently in mid-range BW. But mid-range BW still requires FW techniques and handling (biofilters and mecanical filters and high-level water changes frequently done). But SW is expensive in and of itself. For GSPs it is more practical to take them up the full marine conditions and use live rock, skimming (a,k,a, foam fractionation), and marcoalgae refugia (SW techniques, not FW techniques). This is more practical (cheaper) to operate than mid-level BW and gives better and more stable water quality than FW techniques. Ceylons seem to need the same handling as GSPs, but we do have less good info on them long-term in captivity.

HTH

[Pufferpunk]

how do I figure out how much salt to put my tank

viewtopic.php?f=5&t=19348

[geronimo69]

Thanks for not making a liar out of me RTR!

Thanks for the great info also.

[RTR]

Always glad to help. I think....

[GspWinniefred]

Hi, just wondering if possible you could talk a little more about the cost effectiveness for gsp being in brackish water vs saltwater? Thank you