The Puffer Forum

what gravity do you keep ur brackish tanks at? and roughly how much per 10g? thanks.

It depends on the fish, both species and size/age can affect it. Some do just fine in lower salinities, so you can save money by using less marine mix (salt).

Others prefer higher levels, so you mix accordingly. What kind of fish do you have?



Whatever you do, there are two main things to keep in mind when making brackish water.

1. Use marine mix, not "aquarium salt". You want a blend of freshwater and seawater, not freshwater with some salt in it.

2. Never raise the specific gravity (its how you measure salinity levels) by more than .002 per week, or you can kill your bacteria and cause the tank to re-cycle, potentially killing your fish or at the very least, causing ammonia poisoning. You can figure an additional tablespoon per week will not raise the salinity too fast in any tank larger than 10 gallons, but its best to have a hydrometer or refractometer so you know exactly what your levels are rather than guessing. There really is no way to tell you exactly how much salt you need to reach a certain salinity, because each person will measure differently, things such as age and humidity levels will affect how the salt actually affects the water, different brands will need different amounts, etc.

hmm ok, yeah i was jsut looking for a general, so i should be looking up spesicif specie. I work in a fish store and were jsut starting in the brackish, and i was curious on how much salt to use. right now were using 5 tbpsns of instant ocean per 10g. im using a drop tester and were keepign it about .24% salt, if that means anyhting haha. I think its alsmot too low to read atleast on our hydromoter, its right at the bottem basicly. right now wrre keeping fig 8 puffers, mollys,rainbowfish, and some gobies mainly. It seems everyone i talk to has a different opinion on how much salt to use in a brackish tank, so i can see whay it would be different depednsing on the fish.

Figure 8's, Mollies and gobies will do just fine in a lower salinity. What you have them in sounds like it would be only around 1.0015 or thereabouts, which is barely more than freshwater. But its better than no salt at all. 1.006 would be much better for the fish, but maybe there are reasons its being done that way at your store, ask your manager to see why its done that way.

The rainbowfish, well, it will depend on the species. Some do okay in low brackish levels, some prefer freshwater. At those levels, it probably won't matter to them at all.

great thanks for the info! il see what i can do im good frinds with the manager, and theres no specific reason for the rateo other than its its sjut what hes herd other people use i think haha, il put in my 2 censt because i thouyght it should have been higher aswell. for raintbows right now were keeping bosmoni, and precox, but we also get reds,autralian,threadfins, turcoze(sp?) and thats usualy the main ones.

Just make sure the folks that buy your BW fish, cycle thair tanks at that SG.

yea deffitly, tha would kill all the bacteria pretty quick i bet.

Also a shock to the fish if they just dump into their FW tanks.