Interesting topic. I have had a reef tank for about 10 years now and I found this following article and study extremely interesting. It answered a lot of my questions about this topic.
Article: (do a search)
Bacterial Counts in Reef Aquarium Water: Baseline Values and Modulation by Carbon Dosing, Protein Skimming, and Granular Activated Carbon Filtration
By Ken S. Feldman, Allison A. Place, Sanjay Joshi, Gary White
This study was done to evaluate carbon dosing, protein skimming, and use of activated carbon, and their effect on bacteria population in a salt water tank, but it answered other questions for me. What made the study unique was the new piece of lab equipment used to measure bacteria count in the water during the testing.
The data was an eye opener to me and explained why over the years, I have never been able successfully combine and grow softies and SPS together, when using an efficient protein skimmer on the same tank. I have kept them all together, but not what I would consider successful over a long term. The soft corals often were stunted, and grew little, while I skimmed heavily. I have normally heavily skimmed, used activated carbon, and carbon dosed my tank. The eye openers to me were the bacteria data and charts; more than what they were testing to prove.
I think we can all agree, as a generalized statement, that bacteria constitutes a major food source for both softies and SPS, which both are mainly all filter feeders, feeding on different forms of plankton and largely bacteria plankton. Soft corals are mainly soft tissue and thus require more food than SPS. Probably why it is often said softies like dirty tanks. SPS have a very small amount of soft tissue and grow in size largely from building their calcium structure.
What I found most interesting in this study was that the average in the wild coral reefs have a rather high average bacteria count in the water surrounding them. Probably averaging closer 1500 Bacteria/ml. around the world. This is 10 times more than what is normally seen in a skimmed reef tank.
The Sanjay non-skimmed tanks used in the testing would always settle back down to close to a natural reefs bacteria count as the coral consumed the increases in bacteria caused by feeding during the tests, as the coral grew and consumed more as much food as they needed, and ended with a bacteria count closer to a natural reef count.
The skimmed reef tanks, using a good skimmer, quickly reduced the water column bacteria by nearly 90% of that of an average natural reef. SPA tanks using an efficient skimmer, normally feed bacteria and plankton like food, or use a system similar to Zeovit that re-introduces and grow high quality food value bacteria to feed the SPS coral to make up for this skimmer export of bacteria.
Does than mean you cannot row SPS and softies together ....No, reefers do it all the time. But, I think most of agree that an all softies tank has totally different filtering and feeding parameter than an all SPS tank. Both SPS and softies can adapt and acclimate over time and grow together. But I believe softies do best in a non-skimmed, or at least lightly skimmed, system simulating a natural reefs high bacteria count.
I always marveled beautiful soft coral growing in two 125 gal. soft tanks at my local fish store. Both tanks over ten years old and have a huge collection of large mushrooms, xenia, and leathers totally filling out the tanks. All they do to maintain them is add lime water for make up, partial water changes when they think about it, and feed the fish. They donโt even have skimmers on the tanks.
Read the article. Very interesting and detailed. I am sure my comments will get a lot of comment.
