Filtering water for the humidifier

Hi All,

I recently added a couple of small humidifiers in my veg tent. It was so dry in there, it was having a negative affect on my plants. My plants are much happier now.

But my carbon filter canister on the other hand, isn’t at all happy. Within a week of adding the humidifiers, my exhaust flow has diminished quite a bit. I think it’s the filter, I already have a replacement on hand so I’ll be testing that out probably tonight.

I’ve just been using water straight from the tap. My tap water is pretty good but there is definitely some mineral content. My plants don’t mind it, so there’s no way I’m going to start buying bottled water just for the humidifiers.

My question is, how much filtration is enough. I’m debating whether to get one of those inline RV water filters (single or triple?) or whether I should go with a small RO.

I have a 55 gallon rain barrel in my grow room which is currently unused. If I had to go full RO I might use it to catch some of the “waste” water to use on my plants.

What do y’all think?

I have owned ultrasonic type humidifiers that went t.ts up with tap water, and those that could care less. My current Honeywell unit mentioned nothing about water, and ran all winter with no issues on tap water. I’d go with a new humidifier unit or two if need be rather than screw with carrying water.

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@CurrDogg420 This is the air filter exiting your tent, not any filter attached to the humidifier, right? I wonder if your filter has done its job, filtering out shit in the air, then with the added humidity, that shit started to grow! Or at least turn into an air-blocking paste.

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@CurrDogg420 I like the ZERO water filters…use them for hydro and humidifier.


@spudgunner, you got it, I was talking about the exhaust filter for my tent. I guess it has been running 24/7 for 8 months now, so maybe that was “my money’s worth” for this canister anyhow and the timing is just coincidence.

I had been anticipating this happening though to some degree. I heard a discussion about it (hard water having a negative effect on carbon filter) on a Mr Grow It podcast. I sometimes feel like some of the stuff he says is a bit “confirmation biased” though. But when it kicked in a week, I was like :thinking:

@retiredoldguy one of the first things I did was look up your thread there, because I remembered you saying you had good results in your hydro setup. Is that line all brita type jugs though? I was hoping more for something I could hook right to the spigot.

@CurrDogg420 You can get brita filters for your taps…

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@CurrDogg420 What I have done is I took the lid of a 5 gal bucket and cut a hole in the top…now I place the ZERO water filter/reservoir in this hole and let the water drain into the bucket. I make my water while I am in my room doing other things. THe reservoir is 1/2 gallon and takes about 3 minutes to drain so make a gallon every 6 minutes or so right in the bucket I will add the nutrients to. I make nutrients in 4 gallon increments.


@CurrDogg420 I recently purchased the green rv water filter"i forgot the brand"but it works great pH is on par when you break the filter in but the water is cleaner it’s worth the :moneybag::moneybag:, I would definitely use it in the humidifier it will run cleaner and last longer


Freakin’ brilliant. TY for sharing. I love Zero water and the results. I just couldn’t handle the small jugs. TY for posting. I have an inline on my grow room sink, so need to test end result of both filtered H2O results. Any chance you put a tap on the bottom of the bucket to dispense or just dip out?

@GrnyGrows I use this long stick water pump to transfer nutes or just plain water from the buckets to humidifier or reservoirs. Easy to move 4 gallons in a 5 gal bucket and then use the pump to do the transfer…and that same stick pump is how I get all the old nutes out of the reservoir when I exchange it

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Great idea. I appreciate your help so much.

Take it off unless the smell is really a issue I love the smell of nugs fresh buds oh yaaaa