Nice guide, very helpful.
But still, I would love to share one mine experience... When I moved from Europe to Tobago (Caribbean island) where I currently live, I was shocked when I visited one amazing beach. In fact it's a small bay with very shallow water (for the most part of the bay water is knee-deep or waist-deep)!
That shallow water is full of corals - all kind of corals, and, what is most fascinating for me - countless Zoanthid colonies! Like a carpet!
Why am I saying this?
The point is that some of them live in very small - few centimeters deep hols in the rocks on the beach! Unbelievably! In small hols on the strong Caribbean sun - can you imagine temperature in those hols? And they are wide open!
Also, they live everywhere in that shallow water....
Also I was curious and I tested water quality on that reef and on many other reefs around the island - and I was very surprised that many reefs don't have such a perfect water quality at all! Ammonia was present in some of them (especially in that shallow reef) - believe it or not! But still, everything is very alive!
My point is - people, maybe we pay too much attention to the water quality and all those things. Everywhere on the internet where i read about reef aquariums I read all the time about water chemistry... quality.... but even in the nature itself water is not perfect!
One more interesting thing - on all reefs here salinity is much higher. Usually specific gravity is around 1.030 or even higher!
It's lover on some beaches which are not near coral reefs....
Yeah, I took few Zoanthids from that shallow bay/reef an put them in the aquarium, and after few minutes they were wide open. And after few months they look very happy.
Only problem which I have is bluehead wrasse which (from the reason unknown to me) loves to swim above Zoanthids all the time and often he touches them, and they close! First I thought maybe he likes to swim in the water flow, but even when I moved Zoanthids he just suddenly changed his swimming route and there he is - above zoanthids again! I even think to get him out of the aquarium!