1993 Nissan Maxima Changed Belts After Running Min Engine Realized That Needed

I changed all the belts but after running for few min the engine I realized that I needed to replace the water pump too. So, i opened again everything and I saw that the timing belt slide to the limit of one of the sprokets. Did I put not much tension on? Cheap timing belt? Thanks for the help and eventually for the suggest to what I should do.