Humidifier, do I really need to fill it to the line?

[DocWils]

Oy. Distilled water does not automatically equal sterile.
As soon as you crack the lid on that jug, it isn't sterile.
Keeping distilled water in there a week is no better (or worse) than keeping tap water in there a week.
During the night, you are heating up the water. This invites all sort of wonderful stuff to start growing.

In other words, dump the water each night no matter where it comes from. Or keep it if you're lazy like me. (and I use tap water!)

Correct - it is wiser to dump water every day or at most every two days if you use distilled water - growth occurs more quickly than most would think.

[Homerec130]

I use distilled water and dump it every other day. Most of the time my humidifier is off and I use it just for pass over moisture so I don't use that much water. When I am on the road, I dump it every day as I am moving the machine from the bed side to the cabinet (so it isn't out in the open).

Breathing too dry air can do a number on your sinuses. I should know, I used to breath aviator's oxygen for hours on end. Unlike medical oxygen, there is no moisture added. On top of it, most aircraft systems also had a drier to take any water out. Water is bad - it freezes up the line. Frozen line - no oxygen.

Homer

[Sparkle]

If you are fine and comfortable without a humidifier, then you don't need to use it.

The humidification is for comfort and I would guess that if the ambient air is bone dry then that's when humidification comes inti it own

Thank you - yes - I am comfortable without it. I look forward to what the other seasons will bring and am grateful to have it as an option.

[zonk]

For zonk, the humidifier is part and parcel of PAP therapy ... not just a comfort thing

As for H2O, I fill the water tub just below the max line with clean fresh drinking Sydney tap water every night
I've been doing this for more than 4 years and not suffered any malady ... ymmv

Follow manufacturers recommendations for best outcome ... use only distilled water, dumb the water and wash the tub daily

[Jim Bronson]

Tap water here is very hard, so I use distilled. I've been topping off the tank daily and wash it in warm soapy water weekly. When I travel, I probably won't have access to distilled, so I'll have to use tap.

[archangle]

Oy. Distilled water does not automatically equal sterile.
As soon as you crack the lid on that jug, it isn't sterile.
Keeping distilled water in there a week is no better (or worse) than keeping tap water in there a week.
During the night, you are heating up the water. This invites all sort of wonderful stuff to start growing.

In other words, dump the water each night no matter where it comes from. Or keep it if you're lazy like me. (and I use tap water!)

Germ growth will be a lot slower in distilled water because there's almost no food for the germs to eat. Germs can't multiply without a source of energy and vital nutrients. Also realize viruses can't grow in water at all, they need to be inside another living organism.

For instance, protein synthesis requires nitrogen, and most germs can't pull nitrogen out of the air, they require nitrogen compounds that aren't in 100% pure water. They also need an energy source, and there's nothing in pure water for them to feed on. Algae might grow if there's enough light hitting the water, but even algae needs available nitrogen and other trace elements.

That doesn't mean there's absolutely zero germ growth in distilled water, just that it's a lot less than with tap water. Dust from the air provides a small amount of food, and distilled water isn't 100% pure. It also concentrates the gunk as the water evaporates. If you've topped it off 3 times, it's at least 3 times as dirty as fresh distilled water.

Airborne germs from the air may fall into the water, but you're breathing them anyway, even if you're not doing CPAP. Unless they multiply in the water, the number of germs doesn't increase vs. what you're breathing without CPAP.

Also, realize that, in theory, germs in the water stay in the water. As the water evaporates, the germs stay behind unless the air is so forceful that it's generating droplets, which the machines are designed not to do unless you overfill the tank.

I keep topping my distilled water off, but if it's got really low in the tank, I go ahead and dump the small amount of water out even if it hasn't been a week. I clean the tank weekly.

[novatom]

On Friday night I decided to fill the tank only halfway. About 5 a.m., I was awake and all of a sudden noticed a leak coming from the humidifier. The leak had a slight "whistling" sound and was big enough to register as a "large" leak on the machine (probably my first ever). I thought it might be the hose, until I removed the tank and noticed that there was not much water left, barely enough to cover the heating plate. But I still didn't understand why the lack of water would result in a leak.

Anyways last night I filled the tank up and there were no further problems.

[Crimson Nape]

After getting "thumped" for not replacing the distilled water each day, I came up with a compromise. I filled the S9's reservoir with 12 ounces (350ml.) of water last night. This morning I poured out the remaining water into the measuring cup. I found that in 8 hours I consumed 4 ounces (118ml.) Based off a 1/2 ounce (15ml.) per hour usage, I filled the tank with 6 ounces (178ml.). Knowing I'll never sleep for 12 hours and to allow for changes in humidity this should minimize waste. I have this thing about wasting stuff. . .

[surferdude2]

As regards my ResMed S9 with H5i humidifier, I find that when the water level gets lower the humidity output goes higher. I can run 7 hours on the high setting on a full tank without a problem and have a small amount of water left over. When I stretch it to 8 hours, the last hour creates hose condensate and the gurgling sound of percolating water when I inhale. When I check, the tank is empty. That stands to reason since the humidifier plate is running on a timed pulse interval basis and has no feedback relative to humidity being delivered. The last 1/8" of water evaporates much quicker and the humidity rises accordingly.

Lesson learned; To minimize the humidity variation, start with a full tank regardless of the chosen setting. Furthermore, if running at the highest setting and extended sessions (>7 hours), rain out is more likely, especially if the room temperature is cool (<70° F.).

[DocWils]

But I still didn't understand why the lack of water would result in a leak.

It wouldn't. Leaks are measured at the mask point, not the tank, so if there is a leak and a whistle from your tank when the water is low, then it needs replacement.

I run my CPAP with the tank empty (and card out) for around 40 minutes to an hour each day to dry the tank, hose and sundry, there is no whistle.
Most mornings when I wake up there is barely enough water left in the tank to cover the heating plate, no whistle and no recorded leak. This is clearly a mechanical fault in your system.

Caveat - there is sometimes a "back sigh" or murmur on the out breath when the tank is nearly empty and your pressure is close to max, this is an echo that can be removed by hitting the "ramp" button to relieve the pressure for a while (it sets you back to the start pressure and ramps it back up over 20 minutes - it is a bit unpleasant for around half a minute until you adjust to the rapidly lowered pressure, but then it gets better quickly and you are back asleep). If that is the whistle you are referring to, that is the fix, but there is no way that this will register as a large leak.