Shake well before using. Soak any food in GarlicGuard before feeding. This solution is safe for use with medicated foods (to attract the interest of finicky eaters to the medicated food). For example, to enhance effectiveness against Ich and other harmful parasites use Seachemâs Focus and MetroPlex as follows: Add 1 measure of MetroPlex to 1 measure of Focus per tablespoon of food. Completely soak this food mix in GarlicGuard, refrigerate the mixture, and feed once or twice daily for 1-2 weeks.