Salt and cats (plecs and corys)

[criffa]

I really hope someone can help me sort out the answer to this question. It stems from my paranoia of using resins in the filter because of the other ions they can kick out (nitrate removal -> chlorides and water softening ->sodium?). I've heard from a few sources and witnessed it first hand how most catfish dislike salt (and Iâ??m assuming that it's the NaCl variety). So the question/s is/are what is it about the salt that catfish dislike? Is it the sodium or chloride or both? Or is it the higher ionic concentration of water only? What levels can they "tolerate"? If resins exchange one ion for another, then this could lead to potentially high levels of chloride (for example's sake). Am I right to be paranoid about ion exchange resins?

Cheers in advance!

[Barbie]

Water changes are a far better idea for nitrate removal than any resin. There are other forms of dissolved organics and what not that will also be removed by dilution through a regular water change regimen. While most cats can tolerate low levels of various salts, there is really no need to take the risk with them, IMO.

Barbie

[Silurus]

Is it the sodium or chloride or both?

I would think the former, since sodium is physiologically more important.

[zenyfish]

I've read low levels of salt can be benefitial to fish:

http://www.geocities.com/CapeCanaveral/ ... ml#osmosis

We have mollies and a common pleco in the same tank. Mollies like a lot of salt, though I've read farm bred mollies don't need as much. And I'm afraid too much salt will harm the pleco.

What I'm asking is:
How much salt can I add and still have the pleco be comfortable?

Thanks!