Betta with whitespot

[basia]

Last week after doing a 20% water change I noticed my Betta had whitespot. I treated the water with Interpet whitespot treatment. Yesterday I gave him the 2nd dose and he had no spots on his body at all. Today he has white spots on him again. He is eating but is very lethargic and spending a lot of time sitting on the floor.
This is a fairly new 6 gallon tank. He is the only fish in it. My test results for the last 2 weeks have shown Amonia 0, Nitrite 0, Nitrates 5.0, pH 7.6. I usually do 10% water changes every week and add Stress coat to the water.
What am I doing wrong?

 

[WILDER]

Is he getting stressed, and are you putting the water back in the tank at the correct temp, add some salt turn temp up, add an airstone for aeration, can you cover the tank up so it is in the dark.

 

[basia]

I check the temperature with the thermometer which is in his tank so it does go back in at the same temp. He may be stressed, he hides in his plants most of the time but he doesn't have any tank mates to stress him. He doesn't like airstones, I had to turn his filter right down, moving water definitely does stress him!
I have already turned his light off. The temp in his tank has been 80 since I had him.
I just don't know what to do with him, I don't want to lose him.

 

[WILDER]

It can come back as fast as it went away, turn temp up abit more usually you turn it to 30, do you think the temp at 80 all the time is stressing him out.

 

[basia]

Maybe - I'm very new to fishkeeping.
I read on the Betta thread that they like it warm and my tank seems to just settle at 80 but when he's better I'll turn it down and see if he livens up a bit.
I have bought some WS3 which Bettaman was recommending to another poster but I haven't used it because I was already treating him with the Interpet. Should I wait a few days, do a big water change and then try him with the WS3?
Thanks for the replies by the way Wilder.

 

[WILDER]

Yes completely get rid of the old med out, before you try another manufacture, good luck, don't be to worried it usually takes two courses of meds it did when i had it once.