http://www.ebay.co.uk/itm/VIZIBLEED-...8AAMXQNo5TY41J
I have used this with good results...tbh its as effective to use a piece of clear silicon tubing that is a tight fit over the bleed nipple.
You only need to crack the bleed nipple open a 1/8 or a 1/4 of a turn.
Im not to clear if you are allowing air into the system from the top res..ie by letting it bleed dry and drag air in