Most of us have to deal with holding tanks, and they can be no fun at all. A totally natural product that can take a lot of the "YUCK" out of it:

Marine Digest-It

Ever had a clogged head?  Or a holding tank that couldn’t get completely pumped out?

Want to be able to use regular toilet paper instead of that super-thin stuff that’s marketed for holding tanks?  (There’s another way to achieve this, too — read here.)

Or have the situation that a friend of a friend did — got a new-to-you boat and discovered that the holding tank was basically full of, uh, dried out “stuff”?

Several weeks ago, I wrote about Super Digest-It for clearing clogged drains.  And a little while later, I got an email from the manufacturer’s “brand ambassador” (what a great job!) wanting to send me some of their other products to try out.  Well, heck, sure I’ll try stuff (note: my opinions aren’t swayed by the fact that I got it free).

One of the items that Aly from Unique Natural Products sent me was Marine Digest-It.  Its number-one purpose is to liquefy everything in a holding tank and deodorize it, too (it works whether you flush with fresh or salt water), making pump outs much easier.  An added bonus, I later learned, is that it will clear clogs in the head discharge hose with “no muss, no fuss.”

Three advantages from this:  you can use regular toilet paper and put it down the toilet (I hate that super-thin “holding tank” stuff and it can be impossible to find in some places), you completely empty the holding tank making it possible to go longer between pump-outs, and you’ll have fewer funky smells.

Now, the good thing is that unlike most other “holding tank” products, it doesn’t use harsh chemicals.  As with all their products, it uses helpful bacteria to take care of the problem.  The company is emphatic that their products are not bad for the environment yet work well.

Okay, so my problem was that I didn’t have a holding tank problem (wait, that’s a good thing, right?).  But through friends of friends, pretty soon I found someone who did (he asked that his name not be used).  And it was nasty.

He had purchased an older boat that had sat on the hard for a number of years.  And the holding tank hadn’t been emptied before it was stored. (Yuck, but not all that uncommon.)

Checking things out, he discovered that it was about half full with “material” that had dried out over the years.  He planned to remove and replace the tank, figuring that there was no way to remove the dried out stuff from the tank. Filling the tank with water and letting it sit hadn’t done much so far.

I asked if he’d be willing to try the Marine Digest-It as a test case.  His reply was something along the lines of “Well, I know that as it stands, I have to replace the tank.  I don’t see how it can make the situation worse, so sure.”

I got a report back: it’s working.  The tank isn’t totally empty yet, but quite a bit of progress has been made in just one week (they can only get it pumped once a week).  (UPDATE: After the second week, it’s clean).

If the Marine Digest-It is working in this situation, I have to think it’ll be good for regular use.

The company recommends adding some after every pump out.  They say that it is also good for cleaning the bilge and any areas with fish blood.

I also asked Aly how it would work for a clogged hose.  That is, the discharge hose from the toilet to the holding tank (or overboard when offshore). I know that many boats have problems with this and having to remove the hoses to clear the clog is just plain nasty (I won’t go into details).  She said it’s great in this situation:

What we recommend is pour 8 ounces (1 cup) of product down your toilet, followed by 3 cups of warm water.  Make sure the water is warm and not hot. Then just let it sit in your toilet for 30 minutes and after the time is up go ahead and flush.

During the 30 minutes the bacteria is growing and reproducing, so by the time you flush the bacteria will have had enough time to multiply so that they can coat your drains. In that way it should eat away whatever is clogging your pipe and will continue to keep it clean. 

She added that if your sink or shower have common hoses with the toilet (unusual but some do), you can mix up another 8 ounces (1 cup) of Marine Digest-It with 3 cups of warm water and put it down the second drain to work two sides at once as clogs often happen where two hoses are joined.I’m thinking that this is pretty good stuff to have on board.  I mean, it does the work of a holding tank deodorizer, plus makes pump outs more complete, is good to have on hand in case of a clog and works without chemicals? I particularly like the “no chemicals” part if you direct discharge when offshore.

A 32-ounce bottle costs $12.95 and will treat a 40-gallon tank 16 times — basically less than a dollar a time — or will work on 4 hose clogs.

Unique Products offers a money-back guarantee.  You can buy Marine Digest-It directly from them or on Amazon.  You may find it at Ace, Do-It Best and Tru Value hardware stores in marine areas (not all stores carry it).

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20 Comments
  • Brian Taite
    Posted at 08 November 2013 Reply

    Wish it was in Canadian stores.

    • The Boat Galley
      Posted at 08 November 2013 Reply

      They’ve working on it — so far, their pet odor eliminator is available on Amazon Canada and they’re trying to get the rest of their products into Canadian stores.

      • Andreas Lange
        Posted at 10 December 2015 Reply

        Sounds good,
        would be nice to get it here in Germany

  • Royce Johnson
    Posted at 08 November 2013 Reply

    Can it be used on shower sumps? Don’t want to turn hair clogs into gelatinous plugs (which is what so many of the drain clearing products do while being harsh on seals and pumps) but would love to truly dissolve any plugs. Our sump is very hard to reach to clean it out when plugged, we have girls with long hair on board, and this could be an answer to our prayers.
    Thanks
    RWJ

    • Carolyn Shearlock
      Posted at 08 November 2013 Reply

      Good question — I just forwarded it to my contact at the company and as soon as she replies, I’ll post it here.

  • Janice Sterling
    Posted at 08 November 2013 Reply

    Is there a difference. Between the bottle for marine use and the one for Rv use?

    • The Boat Galley
      Posted at 08 November 2013 Reply

      Since they do separately bottle them, I’m guessing that there is some difference, but I’ll ask my contact at the company.

  • Dierdre Atkinson Wogaman
    Posted at 08 November 2013 Reply

    I am glad to say that we now have a composting toilet and no longer have to deal with those sorts of things. Phew.

  • Janice Sterling
    Posted at 08 November 2013 Reply

    Thanks do much for showing this product. We just bought a new to us boat and the people who I owned her left sewage in the front head tank for a while. Then stopped using it. Now the v berth smells and we have already emptied the tanks. Hopefully its not soaked into the hoses. I just purchased it today. Can’t wait to try it!

  • Leap Of Faith / Quit Your Job And Live On A Boat
    Posted at 08 November 2013 Reply

    Always willing to try something new in this area.

  • The Boat Galley
    Posted at 09 November 2013 Reply

    Here’s the reply I got from Aly at Unique Natural Products regarding the questions that were asked: “To answer questions: our product does not eat hair. However the reason why hair gunks up your drains is it actually attaches itself to build up (such as grease, oils, etc) that have already started to line the pipes. So when the hair comes down the pipes it catches onto the build up and becomes a net for more hair and more build up. What our product does is attacks and eats the build up that has lined the walls and once that is gone, the hair will wash away.

    Also the difference between our Marine Digest-It and RV Digest-It is their usage. If one of your readers uses Marine in their RV it will do the same job. “

  • Marie H
    Posted at 12 November 2013 Reply

    I wondered about using it in the shower sumps as well. Not to dissolve hair; but to get rid of the sliminess and sour smell. Hubby cleans them regularly; but it’s yet another chore. And usually you know they need it when they start to smell. This might make that job less frequent.

  • Andrea Dollins
    Posted at 07 October 2014 Reply

    Hmmmm…I wasn’t that impressed with this stuff. We liveaboard and get pumped-out weekly, I couldn’t really tell if did anything for build up, but it did absolutely nothing for odor control in my opinion. I think Aqua-Khem is still the best for that.

  • Terri Zorn
    Posted at 07 October 2014 Reply

    We prefer Aqua-Khem also. An all natural bacteria choice is K.O.. Both can be purchased at West Marine.

  • Frank
    Posted at 18 October 2014 Reply

    Any ideas on how to help dissolve a big poop that won’t flush?

    • Carolyn Shearlock
      Posted at 18 October 2014 Reply

      Throw some Digest-It in the bowl with some water and let sit at least a half hour. Try flushing again . . . it should work.

      • Frank
        Posted at 19 October 2014 Reply

        Will definitely try this product. Thank you.

  • Koko
    Posted at 18 October 2014 Reply

    Have been thinking of macerate head but have to move object to the blades ..another problem

  • Andy
    Posted at 26 May 2016 Reply

    You can get it at Industrial Paint and Plastic in Canada.

  • Jennifer Hetrick
    Posted at 01 August 2016 Reply

    Love your website! Awesome article!

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