Heater Broke, Now Ick, Culminaris I Think And Maybe More???

Guys I've lost 8 of 10 tetras. Our heater unknown for how long broke, when we finally found out the fish all had bad ick, and now tonight I'm greeted with two dead tetras covered in cotton. Idk whether to treat for ick, bacterial, or fungal or all three!! I'm down to my two biggest black tetras and my betta. I moved the platy x3 and pleco x1 out because they had been added yesterday I put them back in the tank they were originally in, they show no signs of illness at this time. Please help!!

I was originally going to get Marilands all in one cure, but it says it's very low doses of every medication. Would you recommend that, or using the strong stuff like made for bacterial only, fungal only, ick only ect.
I dosed my 20 gallon with apI super ick cure yesterday. That's the only medication I've used.

 

I recommend the smaller dosage because tetras are to little to handle strong medicines

 

Ok. I'll just get the all in one then. Is there anything else besides gravel vacuuming to help get the spores or whatever out of the tank? Cause I don't wanna go through getting my cycle on track, get new fish and them suffer like those tetras must have :'(

 

put the ramaining tetras in a separate tank and leave the tank the tetras are in now and leave it for 3 months that’s what works for me

 

The 20 gallon now only has my betta and two tetras. 8 do not have another tank to out them in yet. I guess I'll just read up on what all my options are. Thanks for your help

 

No problem

 

There's no telling if the other fish may be infected/carriers. At this point, all of them would need to be treated. Moving them to another tank might spread the problem to multiple tanks.