Maybe
Ammonia Concentration Guidelines
Because ammonia's toxic effects appear at levels significantly below those that are acutely lethal (0.09 to 3.35 ppm NH3-N or 1.3 to 50 ppm total NH4-N at pH 8.2), and because some organisms in a reef aquarium may be more sensitive than the few organisms that have been carefully studied, it is prudent to err on the side of caution when deciding what concentrations of ammonia to allow in a reef aquarium or related system.
My suggestion is to take some sort of corrective action if the total ammonia rises above 0.1 ppm. This suggestion is also made by Stephen Spotte in his authoritative text, Captive Seawater Fishes.6 Values in excess of 0.25 ppm total ammonia may require immediate treatment, preferably involving removal of all delicate (ammonia sensitive) organisms from the water containing the ammonia.