Massive micro sized bubbles can actually be problematic for fish if exposed to them in certain and consistent ways. The small bubbles attach to the membranes of the gills and can cause all sorts of mildly problematic to very problematic conditions.
This is one of the disadvantages with PS - another being mineral stripping.
I have run many a FO
tanks w/o skimmers but this is sort of a point of debate - many will tell you it is absolutely necessary and others will say it's optional.
Bottom line is the level of DOC
in your tank. These values are likely to be closely realted to the level of other boi-filtering you have in the tank. If you power your PS down for awhile and monitor everything (Ammonia, Nitrite, Nitrate and PH
) closely, you may find that the PS is totally superfluous.
There is no hard an set rule. And I would suggest being wary of anyone who says that you must definitely use or definitely not use one.