pro and cons of skimming IMO are fairly straight forward.
Pro's:
removes hydrophobic protiens before they break down further into ammonia nitrite nitrate and phosphate waste.
reduces the influx of amino acids through nitrogenous waste breakdown.
removes other hydrophobic compounds that can contribute to water yellowing.
helps increase oxygen levels in tank,
decreases Co2 levels (helping maintain a higher PH)
increases offgassing of volatile ammonia
helps remove room dust particles that find their way into the tank
may help remove some toxic heavy metals in trace amounts
cons:
can reduce calcium levels (calcium is hydrophobic)
does not remove hydrophyllic protiens or wastes,
removes varying amounts of other trace elements, frome barely a trace amount of removal to a rather signifigant amount (eg calcium)
can remove planktonic foods during feeding
decent skimmers are expensive
ok as for over skimming, there just is not much chance of it having any serious impact that isnt easily remedied. whereas underfiltration and cleaning of our tanks can lead to untold headaches. all you will find on overskimming is anecdotal evidence, and hobbyests saying not to do it. you will find hundreds of those, they "believe" overskimming is bad. yes skimming removes some trace elements but if your keeping up on waterchanges in a proper manner that shouldnt be an issue. skimmers can remove planktonic foods, but thats ok since the capture rate of most planktonic foods in our tanks is about 1-2% the rest needs to be handled by our microfauna and filtration. the availabilityof planktonic foods are great for supporting the bio-diversity of our sand and rock but most simply dies and breaksdown in system (aka becomes pollution). its very simple to add more food so i consider it a good thing to remove the excess.
thats opretty much my take on it.
