Salt in water

You MUST use either "aquarium" or sea salt for this purpose. Iodinized table salt contains chemicals that are harmful to fish. I use about a tablespoon a tank (say a half tablespoon per 10 gallons).

This salt point is still open to debate.

People have different and varied views on Salt and the type of salts that are acceptable for a FW tank. For example the iodine point, certain fishkeepers are of the impression that the amount of iodine contained in household salt would not have a detrimental effect on fish health.
Here is a good article on the salt issue written by one of the members here:
RTR - Salt of the Earth - Aqau Source

But at the end it's up to you to make the decision you feel suits your circumstances best......

Heres another link on the "great salt debate"...

The Great Salt Debate

That link, and other great links can be found in the sticky under the freshwater newbie forum.

The salt isn't actually nessasary in a freshwater tank, but it does reduce stress on fish when applied properly. It is perticularly important to use salt whilst treating parasitic infections. As I said before, you want either "Aquarium" or synthetic sea salt, as these are heavy on trace minerals (which are the real point of it). What you are doing by adding salt is slowing osmosis and adding electrolytes to the water. Both are good for fish, however I have also seen people keep fish for years without using a grain of salt.

(unless you're planning on keeping brackish water fishes at some point "aquarium" salt costs less than half as much as sea salt).

For the purposes of osmolarity, any old salt will do, it's just the electrolytes that cells won't let through that matter, i.e. sodium and chloride.

For reducing nitrite toxicity, it's the chloride you're after. I'm not sayin' that if your tank isn't cycled you can just add a ton of salt and make it ok, just that if you're in a fishy cycle, a bit of salt couldn't hurt.

Iodized table salt contains NaCl and NaI. Typically table salt is around 99.8% pure NaCl. A small amount of NaI (iodide) is added to prevent goiters for inlanders. You'll find that sea salt has more iodide than table salt.

I don't know what harmful chemicals QCppg is referring to, but I assure you, table salt is perfectly safe and completely appropriate for FW purposes, such as cycling and treating Ich.

However, if you want a brackish or rift lake system, then you're going to have to buy the appropriate salt.

Salt can be helpful in certain circumstances - e.g., during cycling to inhibit nitrite poisoning; treating ick. Is it necessary? Absolutely not. Many, many people, the vast majority, I'd guess, successfully keep freshwater fish without any use of salt.

Also, to second the other comments re: salt additives: the warnings against use of table salt because it contains iodine, anti-caking ingredients, etc. are bunk. Table salt is safe for aquarium use.

HTH,
Jim

Boosting the osmolarity of water for rain-forest fish has always struck me as the most bizarre of recommendations. This is supposed to be good for them?

I have no issues with short-term therapeutic or medicinal use of salt. Chronic use of salt in whatever formulation as a supposed "tonic" is IMHO an exercise in self-delusion.

Can you say "snake oil?

I've never understood it either. Shouldn't fw fish be all good osmotically in fresh water? Within reason of course. I mean, that's one reason they're fresh water, not brackish or marine. Or am I missing something?

Yup, snake oil. Perhaps it's the view that if "something helps the fish in the short term, then all the time must be even better!". Right...