SALT IN PONDS The subject of salt keeps coming up with regard to koi, so I decided to include a separate page dealing with the subject.
First, there are many koi enthusiasts who add no salt at all to their ponds, and their koi appear to be quite healthy. Many others, however, extol the virtues of salt in aiding the fish' overall health and well-being, as well as preventing and even curing disease. The salt levels recommended by some are quite high, but most of the people whose recommendations I've read recommend a salt concentration of between 1.25 to 2.5 ppt.
High salt levels damage many pond plants, especially water hyacinth and anacharis.
Norm Meck (Click on his name to read his opinion) likes to keep a 3 ppt saline level in his pools, but he does not tell us whether he keeps any pond plants in them.
It is understood that salt that has added chemicals, be they iodine or yellow prussiate of soda are verboten.
Salt (or saline) concentrations are referred to by "parts per thousand (ppt) by weight of salt to weight of water" One gallon of water weighs 8.3357 pounds. Thus, one thousand pounds of water equals 120 gallons. Since 120 gallons equals 1,000 pounds, the addition of 1 pound of salt will result in 1 part per thousand saline concentration.
All one has to do to calculate the number of pounds of salt they need to add to achieve 1 ppt saline concentration is to divide the pool volume in GALLONS by 120. In order to make this ratio clear, look at the following chart:
In order to achieve any other saline concentration level, just multiply the pounds of salt per your pool size above by the ppt you desire, for example, should you have a 2,000 gallon pool and you desire a 1.5 ppt saline concentration, multiple the 16.7 pounds of salt per the chart by 1.5, which will result in 25.05 pounds of salt for your pool.
Another warning: Salt , once added, stays in your pond unless you do water changes. If you decide to use salt in your ponds, (I recommend 1 ppt) you should acquire a salt level testing kit and periodically determine the actual saline concentration in your pool.
As an added aid in calculating pounds of salt needed to achieve a given salinity level, see the "SALT CALCULATOR".
Also, I've included a calculator for estimating pool volume by means of measured additions of salt. See "POOL VOLUME CALCULATOR".
Last modified on January 15,2000
Pool Size(gallons) Pounds of Salt 100 .8 500 4.2 1,000 8.3 1,500 12.5 2,000 16.7 2,500 20.8 3,000 25.0 3,500 29.2 4,000 33.3 4,500 37.5 5,000 41.7 
