Okee spoke with Dennis today about it. Here's the deal. In August he began to specify that it was Nannochloropsis, and since then he has been adding Isochrysis to the mix(Both have the highest concentrations of HUFA's DHA and EPA). The target mix which should be reached next week is 66/33 percent of Nannochloropsis and Isochrysis respectively(currently it's 80/20). I believe(can't remember exactly) that he's toying with the idea of adding tetraselmis to the mix but because it has little nutritional value, he's probably not going to.
We talked at length about the various microalgae products on the market and keeping in mind that this is him marketing his own product, he did have some valid points.
Spray Dried phyto:
No where near as good as the paste product and can't touch the live stuff. Why? Too big. It clumps and rarely is below 70 microns, Rob Toonen says he's tried various methods of breaking it up including ultrasound and it won't get smaller. This is an issue with clams, as they are selective filter feeders and won't uptake phytoplankton larger than about 40 microns. This is stuff is great for sponge growth as it almost immediately deteriorates into dissolved organics. The spray dried stuff is commercially known as Algamac and is used mainly for shrimp farming.
Cryopaste products are good substitutes for live phyto, as it's easier to dose in larger quantities which is why the main users are aquaculture facilities. For the hobbiest, its fairly easy to overdose this stuff because it's so highly concentrated and it begins to rot almost immediately(within hours). Overdosing can cause fairly severe cyanobacteria and other algae blooms. (Seen this myself). Does contribute to DOC's thus can help sponge growth.
The Live Phyto, is much harder to overdose(I've seen it done <g> ). Live is always better than dead, but you won't see as much sponge growth with live because they are competing with the sponge for dissolved organic compounds(DOC's). But Rob Toonen points out and it's a valid statement, that even though the Phyto is competing for the DOC's they will eventually be consumed by something else, and be converted to waste which will become DOC's again, thus you really aren't robbing the tank of food by adding Live Phyto, you just aren't contributing to the overall DOC concentration by having dead phyto rotting in the system.
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[This message has been edited by MickAv8r (edited 23 November 1999).]