Hi Mitch,
Discus are notoriously fussy eaters, particularly when put into a new environment. I've heard of them taking anything upto 6 weeks to come out and start feeding, so I wouldn't worry too much if they look ok.
I'd recommend checking most water parameters regularly with Discus, i.e Ammonia, Nitrite, Nitrate, pH and Temp. If they're not eating the food make sure you remove it from the tank if your not doing so already, pollution will cause Ammonia spikes. Your water changes should keep Nitrates down (if your tap water is low in them if you are using tap).
How long have you had your tank? Has the filter matured? Some Discus keepers recommend maturing the filter for at least 6 months. But if you monitor your water regularly you should be ok.
This is my personal opinion based on a fair amount of research I undertook when contemplating keeping Discus but I think 25% daily could be too much. I beleive 25% at any one time is the absolute maximum due to the possible change in water chemistry. The action the the water being poured could also add stress. I'd reduce to 20% every other day. Obviously larger changes may be in order if you have Nitrite spikes etc.
Hope this is some help. There's some excellent Discus dedicated sites out there, I'd check them out for more info. Good luck mate and hope all goes well!