I strongly concur with getting as much hydration as possible. My brother went into chemo/radiation with a significant kidney disorder, and had been treated for 5 years by a nephrologist. In fact, his kidneys nearly excluded him from chemo because they were filtering at less than 50%, and this was the benchmark for the medical oncologist.
Because ChristineB (to her credit) goes on and on about it, I hounded him to the point of unpleasantness about drinking at least 2.5 litres of water a day, (spiked with lemon juice). His latest kidney analysis shows his kidneys filtering in the low normal range, which has surprised the nephrologist.
I suppose we really don't know, but I put this down to the water, and maybe even the lemon juice, which some reading I have done says has an alkalanizing and anti-inflammatory effect, which is beneficial for the kidneys.
Good luck, Joseph. I'll be looking out for your posts, and thinking of you. Linda