:?: I have tried DT live phytoplankton and ESV - I can't really tell the difference. Are any of the newer products (ie Kent) any better or worse. I have read recent posts on microscopic analysis, but does the microscopic appearance have anything to do with real life results of the product?
In recent experiment Rob Toonen (biogeek) conducted, fresh DTs possessed the most nutritional value. ESV's product is spray-dried, and inherently is not as nutritional as the live phytoplankton found in DT. Cryro-preserved phytonplankton, such as Liquidlife's Bioplankton, also held up against the competition rather well (better then month old DT). Since these are pastes stored in the freezer, they have a very long shelf life as opposed to live DT. I'm not familiar with Kent's Phytoplex.
Keep in mind that observable differences in phytoplankton quality might not be observable to the casual observer for several months.
Based on my 3 years of work in biological oceanography (we did phytolpankton surveys in a few oceans). I would go with DTs. I personally use it and think it really promotes growth.
I'd have to support DT's also. Used it for the past 1.5 years and it has promoted a lot more growth in my tank than the 1st couple of years my tank was up and running.