There is much controversy over the use of salt in your pond.

We'll try to be fair and cover both sides of the issue, so you can make an informed decision on why, when and how to use it. First, when we talk about salt, we refer to the common, cheap salt you use in water softeners or to deice driveways. It can be found at any home improvement store and you want the cheapest stuff they sell.

The only ingredient it should contain is good old rock salt. Salt has been seen as a miracle cure for parasites,fungal diseases and even algae control for a long time, but only now after some time and study have ill effects been found with salt. On the pro side, salt aids a fish in maintaining it's slime coat which helps fish counter disease. It can lower the freeze point in winter. It can help control algae growth. It can kill some parasites and is a safe treatment for Ich and other disease. On the down side, it can create a toxic reaction when mixed with some other treatments (Proform-C, for one), Plants don't like it, lowering the freeze point is not always a good thing when you consider the water is colder when it freezes, and too much salt can have an adverse effect on the osmosis of your pond, causing your fish to absorb too much water and, in effect, drown.

Moderation is the key. A small amount of salt would seem to be beneficial in helping fish deal with stress and improving the slime coat. The right amount won't hurt your plants too noticeably and will curtail algae a little, too. A good measurement would be one pound to every hundred gallons, which would raise it approximately 1 to 2 percent.

Koi love salt as high as 6%, but recent research shows that long term exposure to salt make some disease immune to it. As a general rule, I'd suggest using salt in small doses, one cup to every hundred gallons in the spring and summer, but use professional treatments to treat any noticeable disease that comes along. And be sure you know what effect mixing that treatment with salt will have before you treat! A water change is always a good idea when treating a pond, anyway, and is suggested with most treatments.