I’ve used with salt in a quarantine vat think it was a 0.6 % solution that was a quite a while back but I also used this year in pond without the salt and it worked too I re scraped after 3 doses and all ok but I’ve heard others who have had to dose 4 times

4000 gallons queni koi drum and jbr plastics bio chamber drum fed from bottom drain 3 inch gravity skimmer also into drum 55 watt submersible uv 240 litres air and 12 fishI