Sorry to hear about the yellow tang...it did not look good
I am glad you finally have your own test kits though.....being able to test no matter when is very important. AGAIN....How do you mix your new SW? Do you follow the proper mixing procedures as outlined in a post earlier in this thread? That is also very important
and You MUST get a powerhead or 2......circulation within the tank is extremely important also.
and get some better foods.....mysis, marine cuisine, emerald entree.....and the tang will need algae sheets in their diet
REMEMBER...they grow fast, so if you are truly planning on upgrading, I would start now