A little tip for when to change your Rowa.
put a jug under the outlet from the reactor (you will have to lift the reactor for this) and collect some water, test the water with your phos test, assuming you're using a colour change test make a note of the reading, and leave the test for 30mins, once this time has passed check the colour again to see if you have a different reading, if your new result is worse then your media is on it's way out, depending on how much of a difference there is between the two readings this will tell you if the media needs changing sooner rather than later.
