How much Iodophor to use in solution to sanitize? Well it depends how much water you are diluting it in. In a few gallons of water a couple capfuls will turn the water to a tannish, light brown color. If you can see it, it's in there working. After using it long enough you get to know how much to use by the color of the resulting solution.
Now a classic definition comes from John Palmer's book How to Brew, "Iodophor is a solution of iodine complexed with a polymer carrier that is very convenient to use. One tablespoon in 5 gallons of water (15 ml in 19 l) is all that is needed to sanitize equipment with a two minute soak time. This produces a concentration of 12.5 ppm (parts per million) of titratable iodine. Soaking equipment longer, for 10 minutes, at the same concentration will disinfect surfaces to hospital standards. At 12.5 ppm, the solution has a faint brown color that you can use to monitor the solution's viability. If the solution loses its color, it no longer contains enough free iodine to work. There is no advantage to using more than the specified amount of iodophor. In addition to wasting the product, you risk exposing yourself and your beer to excessive amounts of iodine.
Iodophor will stain plastic with long exposures, but that is only a cosmetic problem. The 12.5 ppm concentration does not need to be rinsed, but the item should be allowed to drain before use. Even though the recommended concentration is well below the taste threshold, I rinse everything with a little bit of cooled boiled water to avoid any chance of off-flavors, but that's me."
Personally unlike John Palmer, I don't rinse articles when using an Iodophor solution but I do let it drain. Also, if you have the means to keep the Iodophor solution enclosed so fresh air doesn't get contact with it, the color will hang in there and it remains active at killing bacteria for a longer time. If you remember when iodine was used on cuts and scrapes, the principle is the same, it is bactericidal. Hope that helps you Sunny. Just remember, the real bane of making mead, beer or wine is not adequately sanitizing your equipment and having it spoil the batch you worked so hard to make. Just be careful, iodine can stain clothes.