Looks like calcium deposits, need operational manual

A weak vinegar/water solution should remove calcium deposits. I either used purified water or I add a tiny bit of vinegar to the water when I use the humidifier to help prevent calcium deposits from forming.

The mix of vinegar to water is up to you, but as a guideline, if you're smelling a strong odor of vinegar, then it is likely that your solution is too strong - try adding some water to it. Rinse with clear water afterwards.

Humidifiers, depending on brand will spit out a little water as that is the Idea to get moisture into the air, but you can try not filing it so full, this one is steam so I would look into owners manual as to how to clean it , you may find that it has collected calcium deposits not allowing it to vaporize the water properly.

You should be able to get a higher humidity rate at normal settings. If you want high humidity above 40% that should be easily done with the high speed operation. The unit may need a good internal cleaning, and use a Vinegar solution to clear any Calcium or other mineral deposits from the misting ports and misting elements. You must use only Distilled or Filtered water, not tap water.

The humidifier and it's tubing may be clogged with calcium deposits and scale. Especially so, if you're using well water or your city's water has high calcium deposits.

Empty whatever water is in the unit and refill it with a 50/50 solution of White Vinegar and Bottled Distilled Water. Allow it to sit for 30 minutes and then turn the unit ON. Once you feel moisture coming out, allow it to run anoter 10 minutes or so. Then turn the unit OFF and empty the remaining solution (if any is left). Now, flush the system by filling it with Bottled Distilled Water and running it.

For future use, I'd recommend that you use nothing but, Bottled Distilled Water.

how long the filter will last depends on your water .. if your water has a high mineral content then that is left behind as the water evaporates from the filter/wick ... the yellow brown sounds like calcium deposits .. calcium is often added to water to give it a good taste .. that may be beneficial for you but will build up on the filter .. it doesn't hurt much until it starts to clog the voids in the filter material .. as long as air gets thru then the deposits will be ok .. normally the filter should last about 3 months .. if you use distilled water (with no calcium added) then much longer .. if you have hard water then less .. there is a tablet that you can add to the water to reduce the calcium buildup .. the manufacturer of your humidifier will likely recommend that .. thats often available from hardware stores also ..

so your choices are:
1. don't worry about it until the filter becomes clogged
2. use the anti calcium tablet or something like ProTec PC-1 Humidifier Tank Cleaning Cartridge
3. use distilled water for really long filter life
4. plan on replacing the filter every 3 months

other types of humidifiers have other problems .. the hot water type gets calcium deposits on the heating element requiring cleaning a couple times a year, usually with vinegar or a calcium solvent .. that takes awhile..

the Ultrasonic type doesn't generally have problems with internal deposits because it blows moist air out including the calcium .. that produces a fine dust on surfaces in your house ..

of those types the filter system like yours is easier to maintain than the hot water type and doesn't leave dust behind like the ultrasonic all work better and longer if the water is pure .. distilled water doesn't cost much but you have to be careful .. read the small print .. some of it will say "calcium added" .. you don't want that .. if you use only distilled water then the filter should last the whole year ..

run some CLR trhough it its just plugged up with calcium deposits from the water put about a quart of CLR in it let set for about a hour then run it through

keep it in a dry for some time and then use some old tooth brush or small paint brush to clean it then rinse it with water and dry it .........

the most practical solution is install a new evaporative pad every year. But if you would like to squeeze "a little" extra life out of the pad . Try soaking it in a solution of 1 part white vinegar to 2 parts water.

one thign that you can do is get a solution for any hardware store or any store that sells humidifiers. then you would take 1 cap full of the solutions per gallon of water. and let it run through your unit.. or if you don't want to do that. what you can do is rinse the tank portion out with bleach and rinse really well. get a soft toothbrush and lightly brush off the build up off the coils. if that doesn't work please let me know and i'll see what else i can do.

possibly calcium or other deposits from the type of water you are using in the unit..........