Are CUC important....sure....are they required, no. I currently have no clean up crew in my tank, going on two years now. Yes, all of the organisms you listed do serve a purpose....but the purpose they serve can be accomplished by more than just including said organisms....which is why I stated they aren't required. Awesome collection of fish BTW Our tanks can't really be compared to nature.....if I could swim around with a magic eraser and clean the worlds reefs, CUC wouldn't be required there either lol.Sorry Waters, but I gotta STRONGY disagree on this. My opinion CuC are VITAL to the over all health and longevity of a marine ecosystem. I have a 300g display with a 125g sump for around 360g total water volume. Here is a list of HALF of the CuC I have in my tank. This batch was added when my tank was roughly 3 months old, I started to see algae creeping into the sand bed. I am using these screen caps from Reefcleaners.org because they give a description of what each type does for your system, and what types algae they will eat.
When my tank was 6 to 7 months old I added the following package.
Tank is a year old now.
I also have a couple peppermint shrimp, a fire shrimp, a skunk cleaner shrimp, a Harlequin Shrimp and some Berghia Nudibranchs in there as well.
If clean up crew wasn't vitally important to a healthy reef system, then Nature wouldn't use the