this may help clear up the issue with the dark urine.. and also the dark color of tren.. tbombz is righht about the compound varying ect..but this is more to do with purity rather than heat they say.. this comes from steroid profiles:
Many people claim that trenbolone has a negative effect on the kidneys. There are many of these claims certainly across the Internet since its use has become more widespread. However, there is no real evidence for these claims, and certainly I have seen many long-term users of trenbolone have kidney function tests that are well within the normal range. Perhaps the reason for this theory is the fact that when using trenbolone, many find that their urine can become a much darker more orange-brown colour. However, this is due to the fact that trenbolone undergoes very little modification or breakdown and is excreted as a rust-coloured oxidised form in the urine.
One thing that you notice about trenbolone is that it is often a golden-brown / rust colour when in oil solution. If the hormone powder is refined to greater than 99.5% purity or so, then the colour of trenbolone in solution actually gives a very light golden colour, much like other testosterone products; however, refining the hormone to this level of purity is extremely difficult. This is why there is colour variation from batch to batch with different underground labs; something as small as 0.1% purity can affect the colour of the final product.