Help!!!! Fish are breathing heavy

[carbon]

Yesterday I did a 10% water change, added a serpent star that i dripped in, this morning all of my fish were respirating heavily, the night before in addition to the water change and new star fish I added 2 new impeller pumps. All the fish ate dinner and seemed fine after lights out. This morning was another story. The salinity in the morning was at 1.027 up from 1.025 previous to the water change. my nitrogen level was at >=0.3 my amonia was at 0 the ph was between 7.7 ~8.0 phosphates were not present. So I came home from work and added fresh water untill the salinity equaled 1.025 my yellow tang hid behind my live rock and is now resperating heavily laying down on the sandand looking not so good! I went out and bought some carbon filter material for my sump and added it thinking maybe it was something in the water that did this, but I can not rule out the fact that I was an idiot and improperly added higer salinity water to my system and then re-adjusted, any help would be much appreciated.

 

[Kurt_Nelson]

...but I can not rule out the fact that I was an idiot and improperly added higer salinity water to my system and then re-adjusted, any help would be much appreciated.

When I read your writeup I did think about the fact that the PWC water must've been a pretty high salinity to jump you from 1.025 to 1.027 with just a 10% water change. I mean really high. That sudden of a salinity increase - as well as that quick of a reduction - could be causing some stress.

It's a good habit to get into to check the salinity of the water in your PWC bucket before adding it to the tank. It's just too easy to lose track of how many "scoops" of salt went in sometimes, and a simple check can really save your bacon at times.

For now, I'd just keep the water parameters as stable as possible and let the fish recover.