Originally Posted by Jmunroe
Just vac the gravel entirely and good each time you water change. Vac the gravel the entire time water is draining from the tank. There is hardly any bb in the gravel it is 99% in your filter. If your tank gets that upset from gravel vac'ing then you need a bigger filter with more bio media. You don't need to do half this week and half next week. That's very old school, under gravel filter mentality.
I would disagree in some circumstances and agree in most. The bacteria actually grows on all surfaces in your tank. Water flow is needed to bring them food so this makes filters the best place for them to grow.
However this all depends on how the tank was set up. The bacteria in gravel alone can keep a tank working. If I then add a hob
filter but do not change my bioload then my gravel will still have 99% of my bacteria. Your biofilter will only grow to handle the current bioload. Thats why the lfs
will advise to slowly add fish and not all at once.
So if your filter and gravel where cycled together it is much smarter to vaccume half or a third a week.
If Dman runs his tank with no gravel for a while then we can say his hob
filter holds 99% of the bacteria and as long as the biolaod doesnt change he can vaccum away 100% and not effect his biofilter.