Noticed a brown hint to my water today

So I carried out a 45ltr water change.  Got the opportunity to use my syphon with the hand starting valve, which worked quite well.  Wasn’t the fastest flow (took about 30 seconds per ltr I reckon) but it was quite fun when my daughter thought that we were milking cows :-).  I think the brown tinge must have come from my mopani wood, I had left it soaking for two weeks and the last water change was clear, but perhaps it is due to the fact that the water I was soaking in it started out warm and then cooled in the bucket whereas in the tank it’s getting kept at 25degrees constantly, which may be leaching more of the tannins out of it.  Will keep an eye on it over the next couple of days, but the process of using the syphon wasn’t bad and I want to do a few water changes over the next couple of weeks as the fishless cycle continues.