I think a few of you are missing what he has set out to do here. From what I read keeping everything the same (including regular siphoning of sediment and the same 10% water change regimin as before) is an important part of the experiment. Keeping all things exactly as they were before allows an accurate observation of any change caused exclusively by the BS/BH addition. Any other changes at this point would skew the experimental model he has constructed and call any improvement or decline into question as to what was the true cause.
As it stands his model will only reflect results produced exclusively by the BS/BH. Perhaps when this addition has had time to completely stabilize and the experiment is complete other changes in his regime can be tried if he wishes to perform a "new" experiment
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