What is the ammonia reading?
Let's get back to the basics with a full descriptions of your setup. Tank size, all equipment, lighting, substrate, livestock.
Did you cycle your tank for the past month?
What method did you use?
Are you sure the cycle is complete?
pH can be all over the place during the cycle.
What are the water parameters in your tank; pH, Ammonia, Nitrite,Nitrate, Calcium, Magnesium, Alkalinity
Mix a batch of water, let it sit 24 hours with a ph
and heater and then test it. Post the water parameters for that too.
Check your pH late in the day after the lights have been on for a few hours.
You might only be seeing normal startup variations, but adding the clowns and getting a ammoia spike should not happen.