Yeah it sounds like your conditions are pretty good. If the spots are solid colored, about the size of a pin head or slightly larger on average, and speckled through out the fish, it is probably ich. Definitely keep up on the medication and follow the water changes the medication recommends. The water changes wont be for your standard parameters, its to keep the medication in proportion and to dilute whatever bug is causing the sickness. You said the fish arrived sick?
STOP the medications. The only time I recommend meds for external parasites are those that cannot be eradicated by salt & higher temps such as gill flukes, velvet, etc. Ich can be very easily controlled/get rid of as long as you follow some basic steps:
--50% Water change (twice a week is fine) -- you seem to have a low bio-load.
--Add carbon to take out as much meds as possible -- you don't need meds for ich.
--temp at 86 is good -- do add an airstone as oxygen is depleted at higher temps.
--add salt -- recommended dosage is 1 to 3 tablespoons for every 5 gallons. I'd recommend 2 tablespoons for every 5 gallons. -- remember to add salt only for the amount of water taken out during water changes.
-- continue to keep your filtration on -- actually, depending on the meds you used, the meds may have decreased/wiped out your good bacteria. Use media from an established tank if possible.
-- do not share nets etc with your other tanks as you run a very good chance of contaminating other tanks
-- this is the part many do not follow, hence the re-occurrence of ich in an already treated tank -- you must treat with high temps & salt for a minimum of 3 WEEKS to make sure it is gone. Just because it is no longer visible, does not mean it is not present.
follow these simple steps, & you will be good. O's are hardy & should have no problems with the higher temps & salt.
p.s. If I were you, take all the substrate out. Consider this tank your hospital tank. best of luck.
