I have had my plecos for about 8 months now, one in each of my tanks. I just read in a different section that salt in the water is very harmful to the plecos. Is this true? I usually keep about one tablespoon per five gallons, but want to make sure this isn't going to hurt them. They seem fine, and very active now, since they have lots of algae to eat. Any information would be very helpful, thanks!