Dead fish & high ammonia

Question
Hi,
I arrived from a two week vacation to find one of my fish (a yellow watchman goby) had died. I did a 20% water change before leaving and replaced filter media one week before that, and all readings were normal previously. The person watching my fish had not seen my goby for several days, but assumed he had been hiding. I have done another 20% water change, and added AmmoniaLock, but the ammonia level is still high (5 ppm)and I am very concerned about my other fish. It has been four days and the level has not fallen (or risen). The goby likly passed away about one week ago, so the ammonia has been steadily rising. What else can I do to stablize the tank and reduce the ammonia level ? Thanks

ps- I have a 46 g FO tank with a yellow tailed damsel,a royal gamma, two clownfish, and several snails/crabs

Answer
get some powerheads pointing at the surface of the water, this will stabilize your PH and aid good gas transfer (PH is something that contributes to ammonia levels) i would only feed every other day (perhaps you tank sitter overfed contributing to high ammonia) also try using carbon in your filter.

luckily the fish you have are pretty hardy fellas so they should be ok, if you don't notice a drop in ammonia levels after taking the above steps do a few small water changes, 20% is a little too much to do at 1 time as it may stress the fish and lower their immune systems, they may get sick quicker due to the ammonia lavels.

let me know how you get on.