Hello;
IMHO -- I think there is a balance between biological and and straight mechanical filtering that should be maintained. Tank loads and filter feeders, live rock etc,. are all a part of this cycle. I am sure any known means of filtering will do if it is sufficient to handle the load of the tank.
Mark Peacock -- on your question --- I turn off all filters including skimmer when I feed my food mix. I let it feed for 30-minutes before turning on my filters and once a week I feed at night after the lights go out for some of my Gorgonians. I believe the filter is necessary in my tank and it keeps a lot of matter from landing on my live rock etc,. My Fluval and skimmer remove waste quickly after feeding and keep the tank cleaner. If you have a high load of filter feeders and feed small particles and juices as I do --- the tank may be able to use all you put in and stay clean.
Maybe, you are removing food before your Coral can properly feed. If all else is the same from before and after installing your filter.
I also, feel that all water should be filtered, before being blown around the tank (many talk about their dirty live rock) and filtering can help keep it clean along with good flow and an occasional blow off with a turkey baster.
I feel Carbon is part of the insurance policy to remove toxins, heavy metals, and DOC's from an Aquarium. There is nothing like a large basket for this to keep water crystal clear .
I have found over the years that a filter will only create Nitrate if there is something to convert. I have added extra filters and different types to my tanks to see what exactly happens on fresh and saltwater. There has been very little change in Nitrate with good filter maintenance. I have found a UGF filter to be the best at freshwater and very easy to clean. I also, use a mechanical filter for Carbon and mechanical filtering.
I use a UGF on my reef 1/3 on the left side and use my Fluval for filtering the water and as a Carbon filter --- it is also a biological filter as I keep one basket of good open pore ceramic media ( pieces of live rock works well ) that creates and removes some Nitrate. I clean all but the ceramic media under tap water as I do not care if I lose the extra biological filtration, my UGF is more than I need for my tank load. On the right side of my tank I have a deep sand bed. I feel all are benifical.
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"Any two variables which do not commute cannot be measured simultaneously — the more
precisely one is known, the less precisely the other can be known."
Heisenberg - "Copenhagen interpretation" of quantum mechanics.
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Enjoy!
OFM