help

What do you dose? (kalk, vinegar, vodka, calcium, iodide, ect)
How often do you dose?
When was the last time you dosed?
What filtration material/equipment do you run? (Skimmer, reactors, denitrator, GFO, Carbon, biopellets, ect)

As Nikki stated an imbalance in Alk can irritate coral making them not open fully but wouldn't cause cheato to die nor the ammonia spike but Alk is a major player in reef chemistry! Alk can control the levels of your pH, calcium, nitrates, and more.

Do you have any way of testing your Alk?

Dieing cheato is usually a sign that your Phosphates have reached 0 and that it is starving. If the cheato is dieing it is possible it could cause a spike in ammonia and also release phosphates back into the water which could feed the recent algae growth.