That is scary!
Surely they wouldnt do that to all tanks that are run off that system in 1 day..
I'm sure a few tanks on that system would only equate to a small % of water the overall system..?
Also i wasnt saying the BB dies within the time you do a big waterchange, more as a result..
Fresh water is of course good, but smaller waterchanges wont cause big fluctuations in water parameters..
For those of us that have been in the industry many years, we have the know how to avoid such things, but should assume everyone does when giving advice..
(Noone has even asked about normal water params, filtration system, maintenance routine etc)
I tend to err on the side of caution when giving advice, and be very specific if there is any chance of problems occuring..
I don't doubt you have done this in the past without problems, as i have done big changes myself without problems..
But i have also seen bad results and the loss of a lot of expensive fish..
This IS a possibility as i have seen it many many times and had to help to rectify this problem more times than i would have liked to..
Im sure you have your reasons for your beliefs as i do mine..
and i think i would be flogging a dead horse so to speak trying to get you to understand even though i only made my original statement to warn the OP as i'm basing my advice on FACTS and experiences..
"There's no such thing as civil disagreement, when the ultimate shame is to change one's opinion."
Looks like we both have our own opinions, as learnt through our own experiences,
So we should just leave it at that ?, as it wont help the OP to say much more..