Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: Could you adjust the humidifier level on this unit? I have read some reviews complaining that it's too dry when using KC-850U and they can't adjust
Document: I 'bought it' so to speak, figuratively and literally. While I have no way of objectively evaluating the results I'm getting as a consequence of using the plasmacluster ion generator, I can clearly distinguish one negative side-effect. Running the plasmacluster overnight significantly lowers the room's humidity to a level where it can become irritating -- this is even with the humidifier in the KC-860U running. I had to supplement the KC-860U with an additional humidifier in the room to prevent this.
I also don't wake up with a dry bloody nose in the morning. My baby was getting dry skin on her forehead until we started using this and now she doesn't have those problems. For all of those reasons, and just because I can breathe better, I love this thing and can't recommend it enough.
I wish I could have read a review like this before spending over 400 dollars on this product.
My family is adjusted to living in low humidity. 30% would be irritating to anyone coming from a 50-60% norm, but we're usually not too irritated until it gets down into the teens or "bone dry." Even though I have several hygrometers, including the built-in unit on the KC-860U, the readings vary wildly. They're simply not accurate. More subjectively I can tell you that the plasmacluster unit seems to dry out the room badly.
Since this product offers both a humidifier and purifier in one unit, we found a very good idea and based on the reviews posted here we decided buying a unit back in February. We have cats in the house and left the unit in the same room where their litter box is located. It was helpful, specially on the &#34;auto&#34; mode that turns the purifier as it sense the odors.
Despite its rather flimsy carbon filter and tested in various bathrooms and a kitchen, the KC-860 does an excellent job of controlling odors so long as the Plasmacluster feature is used. Pre-filter is built into the unit housing (ala Austin Air) for ease of maintenance. KC-860 uses the same exact filters as do KC-100U/KC-150U/KC-850U for ease of filter sourcing.
During this time, we found that MAYBE our allergies had SLIGHTLY improved, BUT the air in our house became so dry that it only made matters/breathing worse. The air was so dry EVEN WITH USING the humidifier function whenever the unit was on.
This Sharp air purifier w/humidifier exceeded our desired expectations. With three cats and large litter boxes in our onsuite bathroom, the fine litter dust is no longer a problem. My husband who had serious insomnia issues finds he is getting better sleep; perhaps due to the ionizer feature. It is very quiet. After using it for a month and loving the results, we placed an order for a second unit for our house!
This is my second sharp purifier (first one was KC-850U). The two purifiers look very similar, with 860u having a more premium look (metallic on the side instead of white &#34;ceramic&#34;). I was expecting a larger water tank than 850u but it didn't look like it was the case.
I use this product (actually the 850) in my bedroom, I have had it for two months. I use to wake up stuffed but since I began using the Sharp Ion I awake clear as a bell! I have a wood stove in my house so the air gets very dry but this solves the problem in the bedroom, I do keep the door open just a crack. I have recommended this to several friends and the only issue I have is refilling the  water but that cannot be helped.
Answer: No you can't.  I think the optimal humidity level is already set in the machine. I have used it for over a month now.  When it is relatively warm and the heating system does nmt get turned on often, the water in the storage doesn't get used much.  When the night is cold and the heat turns on, water gets used up quicker.  I am happy with the humidifier; it seems to help with my scratchy throat problem.