Zoa shrinking a

[nfa]

Hi ,

I recently added skimmer to my 8gallon nano tank and changed chemipure blue to system..

All of sudden Zoanthids started shrinking (not completely closed) but became smaller in size and looks dull...

I do 1gallon water change every week..

What may be the reason for this?

Skimmer?
Chemipure blue?

Do I need to dose anything?

 

[TheEngineer]

Probably the water is too clean now. What are your nitrates?

 

[nfa]

API shows 5...

 

[TheEngineer]

Hmmm... that should be fine. Try taking the chemipure out and see if it improves.