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  1. #1
    Join Date
    Oct 2006
    Location
    Midwest
    Posts
    282

    Question Attack of the Pink Crud

    My house has an AprilAire 550 bypass humidifier (several years old) which has been working well this winter. However, today I noticed a significant buildup of pink "crud" in the transparent plastic humidifier drain tube. The house has a water softener using Morton "System Saver" pellets. The humidifier cartridge is only a few months old and appears normal, not showing any of the pink stuff. The drain tube buildup is not slimy, has no smell, and is soft/mushy to the touch rather than scaley. We had not noticed any brown hard water stains before or after the installation of the water softener last March. This buildup seems to have happened quickly since it's by the washing machine and we haven't noticed it before when washing clothes. I can clean or replace the tube, but I have no clue as to what's causing this. There is no return air grille in the room, but could it be caused by some laundry product we're using? A relative who's a plumber happened to be visiting us and didn't know what it might be. Any comments would be appreciated. Thanks.

  2. #2
    Join Date
    Mar 2004
    Location
    Grottoes VA
    Posts
    5,856
    Do you have a wife or daughter who likes to cut up red or pink contruction paper? Do you have a buisness in your house and use a lot of red paper?

    Do you see where I'm going with this?
    Karst means cave. So, I search for caves.

  3. #3
    Join Date
    Oct 2006
    Location
    Midwest
    Posts
    282
    karst - thanks for the reply - no, no kids, nothing like that. Don't even have anything in the house that pink color that I know of. That's why I wondered about laundry products - they're not pink but thought maybe some kind of chemical reaction. Also don't understand why it only appears in the drain tube & not in the humidifier cartridge. Sounds like script for a cheap Sci-Fi movie!

  4. #4
    Join Date
    Oct 2006
    Location
    Midwest
    Posts
    282
    May have come up with an answer - recently had to buy some new furnace filters & got some 16x25x1 pleated Arm&Hammer "baking soda" Merv-10's. Perhaps there was some chemical reaction between the filter material & water softener chemicals. I'll try switching back to plain filters & see if that solves it, although there was no sign of the pink color on the filters. Thanks.

  5. #5
    Join Date
    Jul 2002
    Location
    Zelienople, Pa
    Posts
    2,965
    Quote Originally Posted by roymcoy View Post
    May have come up with an answer - recently had to buy some new furnace filters & got some 16x25x1 pleated Arm&Hammer "baking soda" Merv-10's. Perhaps there was some chemical reaction between the filter material & water softener chemicals. I'll try switching back to plain filters & see if that solves it, although there was no sign of the pink color on the filters. Thanks.
    Junk filters...

    The baking soda may have gotten onto the humidifier pad, washed
    through the drain and the remnants began to turn moldy.

    I've seen reddish/pink, mold/mildew.

  6. #6
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,943
    Soft/mushy sounds organic. I would be washing my hands thoroughly after touching whatever it is.

    I would also clean out the humidifier and do a chlorinated treatment of everything. Has anyone in your home had a cold this season?
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  7. #7
    Join Date
    Oct 2006
    Location
    Midwest
    Posts
    282
    No illness of any kind. Used the humidifier from end of February (when we bought the house) until Summer started, then again this Fall. No pink stuff until sometime in the last 2 weeks which was about when I put in the new filter. I'll follow your cleaning suggestions & go back to a regular filter. Appreciate your help.

  8. #8
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,741
    replace drain hose or pour some hot water and bleach thru it to kill whats growing in there.

  9. #9
    Join Date
    Dec 2006
    Location
    Toronto, Canada
    Posts
    29

    Lightbulb I believe I know what the "pink crud" is..

    Quote Originally Posted by roymcoy View Post
    My house has an AprilAire 550 bypass humidifier..I noticed a significant buildup of pink "crud" in the transparent plastic humidifier drain tube... The humidifier cartridge is only a few months old and appears normal, not showing any of the pink stuff. The drain tube buildup is...soft/mushy to the touch.....I can clean or replace the tube, but I have no clue as to what's causing this. ....could it be caused by some laundry product we're using?
    My wife is a microbiologist, with a lot of experience in water quality. She runs the microbiology lab of a very large pharmaceutical company. The lab's primary function is testing the quality of the water used in liquid drug manufacture.

    Since meeting her, I have learned to fear many things I can't see, and things I thought looked "cool" - like the pink crud in our shower. When I first pointed it out to her, I was promptly admonished for not cleaning the shower, and informed that the "pink crud" was bacteria, which could cause infections.

    This pink film - technically called a biofilm, generally appears on surfaces that are usually moist - such as your drain tube. I doubt laundry products have anything to do with it. I'm guessing that your drain tube either has/had blockage and/or horizontal sections, and that the pink biofilm is found in those areas of the drain tube.

    The Aprilaire 550 owner's manual, at the bottom of page 9, under periodic preventive maintenance states; "Make sure the drain hose has a constant downward slope, and is not flattened or blocked."

    The research paper Molecular Analysis of Shower Curtain Biofilm Microbes gives a detailed technical analysis of such films as found on shower curtains....

    highlights of the article:
    Households provide environments that encourage the formation of microbial communities, often as biofilms....

    Several studies have shown that domestic water supplies can be a source of opportunistic infectious agents, and household plumbing accumulates numerous microorganisms....

    (This study's) samples consisted of..... a pink film on a corner of the curtain that was folded over and constantly wet .... a pinkish orange biofilm from a wet shower curtain that was often used and essentially continuously moist....

    The most prevalent types of organisms found in all of the samples belonged to the phylogenetic group α-proteobacteria. Sphingomonas spp. and Methylobacterium spp.....

    Methylobacterium spp., especially Methylobacterium mesophilicum, have been cultured from pink-colored biofilms of wet environments such as automobile air-conditioning systems, printing paper machines, and dental unit waterlines....

    Sphingomonas paucimobilis has a history of infecting immune-compromised patients or persons with predisposing conditions. Infection with S. paucimobilis can lead to intravascular catheter-related bacteremia, urinary tract infections, pneumonia, cutaneous infections, and visceral abscesses In hospitals, sources of S. paucimobilis infections have been traced to fluid in humidifiers and tap water.

    Methylobacterium spp. also are known to cause infections in immune-compromised patients or patients with other diseases that render them prone to infection....

    Our results suggest that shower curtains harbor potential opportunistic pathogens that can threaten immune-compromised or otherwise ill patients.....Frequent cleaning or disposal of shower curtains is indicated, particularly in households with immune-compromised individuals.

  10. #10
    Join Date
    Apr 2004
    Posts
    201
    I was told at a class by an ice machine company that pink mold means yeast (like in a bakery app) and black indicates sugar. They sell a chemical pack to mount inside the machines to kill or at least combat it.
    ...SHEEESH!!!

  11. #11
    Join Date
    Oct 2006
    Location
    Midwest
    Posts
    282

    Update

    Replaced Arm & Hammer Baking Soda air filter with a different type & cleaned humidifier element, drain tube, etc. No problems since then. Apparently as I suspected - some baking soda entered the airstream & there was some chemical reaction between it and the chemicals in the (soft) water supply resulting in the soda settling out in the drain tube & turning pink.

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