For Anyone Who Uses Salt-NaCl

Incorrect. Salt is not salt; there are thousands of salts. "Table" salt is primarily NaCl, but also contains (according to package I am reading) potassium salts, iodides, silicates, and carbonates (as well as a sugar additive). This might work as a medicinal purpose, or even for brackish setups (depending). It is highly inappropriate for many other purposes, including freshwater setups like African Rift Lakes. The salinity in Lakes Tanganyika and Malawi contains more calcium than sodium or potassium. For these, commercial salt mixes with the proper ratio of cations are necessary.

Edited to add: Also, alkalinity is a key issue - bicarbonates and carbonates replace chlorides in hardwater, alkaline lakes; plain old NaCl has no buffering capacity. This would be relevant especially in Rift Lake setups.

Brackish and marine tanks need Marine salt mixes that contain more than just salt in them. But table salt is fine for medicating freshwater tanks.

A salt is an inorganic crystal.

Table salt is NaCl, period. Some Iodide is added to keep people who don't live on coasts from getting goiters. Now that seafood is fairly easy to come by anywhere, this isn't such an issue. The rest of the stuff are likely tag alongs from the refinement process and combined probably makeup less than 1%.

I think that what Must4ng s4lly was talking about had to do with adding a bit of salt to fw tanks to make them healthier. In that respect, she's completely right. I just bought a lifetime supply of NaCl (unfortunately I wanted KCl) in the form of water softener, 20kg for $4CDN. Beats the extra money for 'aquarium salt'.

But, as others have pointed out, if you're looking for a particular setup, i.e. marine or rift, then you need the proper mix.

FastFish, you've used alkalinity and hardness in two different meanings, if I read correctly. True, Cl has no buffering capacity. But the typical meaning of 'hard' water refers to Ca and Mg, not to the anionic species. Whether the Ca came from CaCl2 or from CaCO3 makes no difference to 'water hardness' but a world of difference to alkalinity. But I'm picking on semantics.

for gravel for my next tank, im just going to go to a crappy parkinglot and shoevel some gravel into my pick up and dump it in the tank because rocks are rocks! its all the same!

I think happychem presents the best view on the matter. One question though, is the added iodide ( which is the type we are not supposed to use) harmful to the fish or not in the concentration present?

Hans, I hate to encourage wise guys but I cannot help it this time:laugh:

The point is moot for me.
I never use salt in a freshwater aquarium.

Bill in WI

I don't know enough about fish to say whether or not the iodine in the salt would cause harm. My instict would be to say that since the 'natural' source of nutritional iodine is seafood, i.e. fish, that it wouldn't cause any harm, certainly not in the low conc. you'd be adding. But then again, see point 1.

Before you could get to toxic levels of iodine from iodized table salt, you would have pickled the fish in brine. IMHO, a non-issue but seemingly eternal popular myth.

Iodine is used as a disinfectant. The low concentration may not affect the fish but what would it do the the bacterial culture in the aquarium?