Bleed chance on weapons?

I am making some weapons, with chances of having bleeding in them. For this example i use the Basic Knife, which has the chance of 20% to bleed for 20 seconds, dealing 1 damage every second, making that a total 20 damage.

I was trying to make this, there are no errors in the script, but for some reason the script makes a 100% bleedchance, and the bleeding only deals a total of 1 damage.

This is my script:

-- Main variables

local hitbox = script.Parent
canDamage = true
canEffect = true

-- Configurations

damage = 35
reload = 0.75
effectChance = 2 --/10

-- Attack

hitbox.Touched:connect(function(hit)
    if (hit.Parent.ClassName == "Model") then
        if (hit.Parent:FindFirstChild("HumanoidEnemy")) then
            if canDamage == true then
                hit.Parent.HumanoidEnemy:TakeDamage(damage)
                print(hit.Parent.Name .. " took " .. damage .. " damage")

                local randomEffectChance = math.random(1, 10)
                print("The number of randomEffectChance = " .. randomEffectChance)
                if randomEffectChance == 1 or 2 then
                    if canEffect == true and canDamage == true then
                        canEffect = false
                        print(hit.Parent.Name .. " got an effect")
                        for i = 0, 20, 1 do
                            hit.Parent.HumanoidEnemy:TakeDamage(1)
                            print(hit.Parent.Name .. " is taking 1 damage")
                            wait(1)
                        end
                    end
                end

                canDamage = false
                wait(reload)
                canDamage = true
            end
        end
    end
end)

BTW, i made the enemy humanoid another name so you cant damage teammates. I called them "HumanoidEnemy", and there is another working script that makes the animations.

Thanks in advance