[Solved] How can I make a blur effect whenever I open/close a GUI?

So how do I make the blur of 10 slowly happen when a player touches a brick while the GUI comes down but when they leave, the shop goes up and the blur effect goes to 0 slowly in the background.

I kept testing but it doesn't seem to work for me.

local blur = Instance.new("BlurEffect",game.Workspace.CurrentCamera)
blur.Name = "BlurTwo"
blur.Size = 0
local Delay = 1 -- Time it takes to scroll down / up

function onTouch(hit)

    if game.Players:FindFirstChild(hit.Parent.Name) then
        local player = game.Players:GetPlayerFromCharacter(hit.Parent)
        if not player.PlayerGui:FindFirstChild("Shop") then
            local gui = script.Shop:Clone()
            gui.Parent = player.PlayerGui

            gui.Frame:TweenPosition(UDim2.new(.25,0,.25,0),"Out","Quint",Delay,true)
                for i = 0,10,1 do
                    wait()
                    blur.Size = i
                end
            repeat wait() until (player.Character.HumanoidRootPart.Position - script.Parent.Position).magnitude > 5

            gui.Frame:TweenPosition(UDim2.new(.25,0,-1,0),"Out","Quint",Delay,true)
            for i = 10,0,-1 do
                wait()
                blur.Size = i
            end
            wait(Delay)
            gui:Remove()
        end
    end

end

script.Parent.Touched:Connect(onTouch)