I found that after adding more tension to the Y Belt that the whole printer would "flex" forward, to fix this I added these 8mm threaded struts which hold the printer in the correct position at all times. These have saved me a fair bit of bed levelling by stabilising the positions of the uprights relative to the Y axis front belt plate. Each 8mm threaded strut is about 40cm long but I would advise buying a 1m length and cutting to the right length in place after bolting everything up.