there may be a better answer to this so please add another answer if you think it won't do the job
Below is a picture of my fish tank. It is a tropical fish tank with the water heated to around 24C. I live in the UK and the room temperature can go as low as 16C (night time during winter).
The fish tank has sliding glass to cover the fish tank and then it has a wooden hood to cover the sliding glass. The feeder sits between the sliding glass and the wooden cover.
The main problem here is condensation on the feeder and inside the feeding compartment. This is caused by the high level of humidity between the sliding glass and the wooden cover. It is also caused by the feeder itself being at a slightly lower temperature than the warm air around it. These two problems cause warm humid air to condense on the feeder (similar to how condensation appears on a cold window).
Maybe the real questions are:
How do I reduce the humidity level between the glass and the wooden cover?
I need a hole in the glass so the feed can drop into the water. There are also little holes to allow the various wires and tubes (for filter, lights etc). It is impossible to cover all these gaps, especially the one directly underneath the feeder to allow the food to drop into the water, but I have put some plastic wrapping around as much as I can to prevent that humidity escaping from outside the sliding glass cover. I've then put an old tea towel on top of that. This will also prevent humidity escaping into my living room and adding humidity to room that might cause mold to grow.
How do I keep the feeder a little warmer so warm humid air doesn't condense so easily?
If the feeder and feed is warmer than the air around it, the warm humid air won't condense on it. I'm thinking that putting a usb warming pad underneath or around the feeder might warm the feed and feeder enough to prevent condensation (a bit like having a radiator underneath a window). I haven't tried this yet but I think the logic is sound.
How to absorb the moisture?
I'm unsure how effective this is but I wrapped the rotating feeding part of the feeder in kitchen towel. I have noticed condensation specifically on the plastic and very close to the feeding hatch so it could be that the condensation is actually running into and around that feeding hatch which could be part of the reason why it is clogging up. I'm less certain about this solution tbh!