What medications are you treating your fish with? Other then keeping the temp up is about all you can do. It'll take a week or two for the parasites to die off. Keep at it and don't let it get to you. They should be fine.
*Edit...wait why does the post say velvet and you asked about Ich? Do they have velvet too...?*
they had ich over a week ago, although with treatment it has dissapeared already thank god although I'm still treating for another week or so to make sure it goes away. But now there's a velvet outbreak. No meds then? Just 50% daily water changes and a constant 30˚ c?
Velvet is similar to ICH in treatment I believe as they are both caused by parasites. The raised temps along with water changes and gravel vacs will treat both. I'm not sure what medication you are using to treat the ICH, but often the antI parasitic ICH treatments will also treat velvet. I've read several suggestions of dimming the lights or doing a complete tank blackout as the Velvet parasite gets some of its energy from light. Make sure that when using medications you follow the manufacturer's directions. Many recommend dosing, doing a water change, then dosing again a few days later. If they recommend waiting a few days in between dosages make sure you wait those few days.
EDIT: I'm not sure, but I've read that copper medications like Coppersafe can be harmful to plecos. Double check that, as well as the compatibility with your current medication before starting any new meds.
I have ick clear from jungle labs with malachite green and acriflavine, ill just resume using it. btw I'm leaving from thruday to sunday. Will these fish survive all those days without water changes or treatment from thursday until monday afternoon? And no I don't have anyone to leave them with or anything.