White spot

Question
Hello
Im in desperate need of advise on white spot, my two puffer fish =  porcupine puffer fish and dogface puffer fish. have signs of white spot my porcupine fish more than the dogface puffer.
Ive been treating my tank with a treatment for about amonth now and the white spot seems to go  for acouple days then cum back the next day even worse. i cant at the moment tell ou what ive been using as im at work.
but is hasnt got copper in it as the man at the fishshop said it would affect my live rock and filter system.
I really need to to recommend a treatment that is very affective but doesn't affect more filter or liverock
im currently using FLUVAL U4 filter
I feed my fish twice aday on frozen foods such as musles,brime,mollusks etc

I have currently got a bully fish in the tank which i sadly lost a fish to last night (which am removing tonight) i havent seen this fish be aggressive towards my puffers though, the tank is in my front room so after work at night i do watch my fish alot and i haven't seen this fish be aggressive towards any of my other fish.

I do do a water change of 10% of the tank every other week. could it be the hp is wrong if so what could i do to make it better ?

Apart from the white spot my two puffers are fine they are active and eat very well the are two very lovely fish.
if you could tell me of a affective treatment that wont affect rock or the filter that would be great.
Thankyou
Tina

Answer
Hi Tina,
Sorry to hear about your problems. Without a picture I'm not much use to you at diagnosing an ailment. The fact that they have the spotting you speak of, but still are active and eating, indicates a fungal infection, but thats a guess without seeing. If you could get me a clear picture or at least a detailed description of the white spots I'll be much more useful to you. Such as; are the white spots cottony or stringy? Mucousy or slimy? Are they crystaline in appearance? Are there other discolorations/redness around fins, eyes or gills? These answers will get us to a clearer diagnosis and an effective treatment for the lil guys. The treatments for fungal, bacterial and parasitic infections are all different and dont work across the board. You can get a "universal" treatment from Seachem and a couple of other companies but treating your pets for something they dont have, is unneccessary stress. Copper based treatments are effective and will not neccessarily destroy your biological filter, but they are extremely dangerous to your fish and all inverts if the dosage is not correct. Get back to me and we'll get you going in the right direction.