[untamed]

Originally Posted by Snappy

We have a different understanding for sure. Zooxanthellea are symbiotic algae that live in the gastrodermis and are photosynthetic. They produce carbohydrates for the coral to feed off of.
In a nutrient poor environment like zeovit it is often a deficiancy of potassium that lightens the colours. The coral will expell some of the zooxanthellae it doesn't need in brighter light because their photosynthesis is more productive and the coral only keeps what it needs.
Clams also contain them and interestingly enough I've seen a blue clam go
brown when there isn't enough light. Anyway of course the coral does have a pigment and most zoox are brown but not all. Expelling the brown zooxa lets the coral get the nice colours but it still has them and they are not all brown. I think we are starting to split hairs now.

This nicely explains why one component of the Zeovit system is designed to cause the corals to expel zooxanthellae. I would guess that this is one component of Zeovit that needs to be used most carefully...