bizsmith@yahoo.com Report post Posted March 21, 2012 I was told that adding Dawn dish soap to the black water tank helps to clean it. Since Dawn is a grease cutter it sounded logical to me. Occasionally I will add about a cup to a 3/4 full tank before a short trip and then dump the tank on arrival at the next stop. It seems to help. Any other opinions? Share this post Link to post Share on other sites
jomarfl Report post Posted March 21, 2012 I've heard of others using Dawn with success, haven't tried it in ours yets, but just might since it makes sense it would cut grease and dirt. Wonder if if affects seals and other things like that though, would have to research to make sure though. Share this post Link to post Share on other sites
dogpatch Report post Posted March 21, 2012 I have never heard of soap. I have always heard fabric liquid softener is the one to use. Share this post Link to post Share on other sites
hermanmullins Report post Posted March 21, 2012 Les, I allways thought you wanted it soft before it went into the holding tank. But I guess after might be OK too. Share this post Link to post Share on other sites
Guest Wayne77590 Report post Posted March 22, 2012 I sure don't want to be behind you when it all catches up and you look like a steam locomotive going down the highway. Suds just a comin' out of the vent. Be very careful with soap in that situation. I use Calgon liquid water softener, and it has made a big difference. it doesn't suds either. Share this post Link to post Share on other sites
bizsmith@yahoo.com Report post Posted March 22, 2012 No suds. It would probably take a gallon of dawn to make suds in the black water. Share this post Link to post Share on other sites
hermanmullins Report post Posted March 22, 2012 I can see it now. A big white van with 'EPA' printed on the sides, chasing a Big Motor Home, with lots of Black Bubble coming out of the Vent Stacks, down the Interstate. Share this post Link to post Share on other sites
36yearsRVing Report post Posted March 22, 2012 I have never used Dawn dish soap. I use yeast and peroxide in my holding tanks to clean them out while going down the road and while it is filling up when camping. It gets rid of solids and smells in tanks. You don't have to wonder if the black tank emptied out all of it's contents. If you want to completely clean out your black water tank, with tank empty, add 4 ounces of yeast, 10 ounces of peroxide and 1 gallon of water. As you are going down the road it is sloshing all over the tank and cleaning it good. A 32 ounce of peroxide at Walmart is $1.00. By all means put water in tank first.The yeast and peroxide both eliminate the solids, not the paper. If you want to see how this works, sit on commode, have a bowel movement, pour in 1 ounce of yeast and let sit in bowl for an hour or so with lid down. The solid will turn into a soft mush. Flush and decide if it is worth trying.Yeast will keep septic tanks clean and helps eliminate solids in tank and you don't have to pump a septic tank our so often. This is the best way to keep your tanks clean and odor free. Share this post Link to post Share on other sites
five Report post Posted March 22, 2012 After dumping the black tank, I put in one cap of Calgon and a gallon or so of water. Every so often I'll put some Dawn in the grey and black tanks when they are partially full, drive to the next CG to let them slosh around, then dump and flush the tanks. Share this post Link to post Share on other sites
Guest BillAdams Report post Posted March 23, 2012 Water and a bit more water works very well also! Share this post Link to post Share on other sites
alscudder Report post Posted March 23, 2012 We have always use Dawn in the galley sink for dishes and washing hand before cocktail hour and that is how we keep the tank clean. I also add some more Dawn to the black water if I know I will be going where there is a dump at my NEXT campsite stop That way all of the tank will have the a good slashing back and forth when I stop. The black water tank is cleaned by the chemicals and when emptying the black water tank completely, I empty the tanks in the following manner: 1. Empty black water completely and leave the valve open/do not close the valve. 2. Open gate of the gray water water tank and wait until the tank has transferred over to the black water tank which will be about half of the gray tank there will be no gurgling of water when done. 3 Close off the valve of gray water tank. 4 Empty the black water tank again still leaving the valve open to the black water tank when finished. 5 Open the gray water tank again to let the two tanks equal out there will be no gurgling. 6 Empty the black water tank again until empty. Close the valve to the black water tank. You can continue this process again if needed. 7 Open the gray water valve and empty the gray water tank. This is a easy process and can be done with one cocktail and if you want to stretch it out a bit, have another cocktail. Remember don't try this while cruising down the road. I have done this method for 6 years and have NO problem ever with my system other than replacing 2 Dupree valves. I have a pump out system in my coach which is THE option to install if you don't have one. When boating I didn't have this type of system (and they were not available) and when you are pumping out 150 gallons out of a boat there are trials and tribulations that you need to know about. With a RV you have options and there is no back up "instant shower of the dirty kind" when you pump out. Thanks for gravity. Happy Trails to U. Scooter and Crew Share this post Link to post Share on other sites
Guest BillAdams Report post Posted March 24, 2012 Water and a bit more water. After 15 years of full-timing we have found that water (and plenty of it) will keep all of your holding tanks (these are not septic tanks and should not be compared to one) fully functional. Share this post Link to post Share on other sites
wolfe10 Report post Posted March 24, 2012 I'm with Bill. Never used any chemicals/soap/etc in the holding tanks-- no problems in over 15 years with this coach. Share this post Link to post Share on other sites
danddferr Report post Posted March 26, 2012 Same here. No chemicals just plenty of water and don't let it get full! OME gauges still work after 4 years too! Dan Share this post Link to post Share on other sites
Briarhopper Report post Posted March 29, 2012 Have to agree with the water and more water contingent. However, to be fair to the soap/chemical faction , Tiffin recommends using Pine Power and several gallons of water to clean your sensors as you drive. If you notice though, all of the solutions (double meaning intended) use a liberal dose of water. Also consider that water and water alone is the single most destructive force in nature. So, I figure 10-15 gallons sloshing around will erode just about anything. Share this post Link to post Share on other sites
scvjeff Report post Posted March 31, 2012 I think I would be really careful with a super sudser like Dawn when using a Macerator. That sounds like a formula for suds cavitation and no way to vent it when the tank is open. Share this post Link to post Share on other sites
drakelos Report post Posted March 23, 2016 Even with the newer style holding tank sensors that are mounted on the outside of the tank, I have had both the grey and black readings showing that they were not empty when they actually were. I suspected sludge build up and tried commercial treatments, Dawn dish soap, water softeners, etc. Nothing seemed to work. I finally hooked up a hose from my bathroom sink and completely filled my black holding tank with hot water (I have an Aqua Hot system, so had unlimited hot water). I added about a cup of Dawn then drove for several hours. After stopping and dumping, the gauge read zero. This also worked on my grey tank. Share this post Link to post Share on other sites
manholt Report post Posted March 23, 2016 In Perry, I had 1/4 full on black tank, toilet read full, could not flush my electric, macerator, Dometic Sea/Land toilet. Added a 1/2 cup Palmolive dish soap and 1/2 cup Calgon along with about 10 minutes of back flushing. Then opened valve and emptied black tank. Before leaving Perry, GA. for Texas, I added the same as before, my black tank is now 1/2 full and I will dump it tomorrow...toilet has worked every time since! I had various foot flush and hand flush RV toilets over 45 years, before this electric flush, and used soap with half a bag of ice cubes to clean black tank when rolling down Hwy and never had a problem! About every 3 months I would add some lubricant by Tethford, never have replaced a seal or knife valve. There is no PD in dish liquid that I know off, nor in Calgon. KISS.. Carl Share this post Link to post Share on other sites
wayne77590 Report post Posted March 24, 2016 Just be careful how much soap you add. Picture this: Riding down the highway at 65 mph and the roof vent is blowing bubbles. Share this post Link to post Share on other sites
manholt Report post Posted March 24, 2016 Wayne. Look further back on this post. Herman beat you on that thought in 2012 ! Carl Share this post Link to post Share on other sites
hermanmullins Report post Posted March 24, 2016 Carl, It's alright, if Milton Bearle can borrow from others , Wayne is welcome to use mine. Now back to the OP. Herman Share this post Link to post Share on other sites
casuall454 Report post Posted March 25, 2016 Although I prefer to drive and "slosh" the tank to break up settlement of solids and then use my black and grey tank flushing systems. I do find watching some videos informative. Share this post Link to post Share on other sites
manholt Report post Posted March 25, 2016 I watched both of the above. Conclusion for me, if your a named product that cost money, you get tested in depth and if your an ice cube, your a joke! So, to me the Jury is still out. Herman. Happy Easter! MB was a very sick puppy! Carl Share this post Link to post Share on other sites
wayne77590 Report post Posted March 25, 2016 Carl, I didn't know this thread was that old (as Herman) and I never take what Herman says seriously. I guess I need to read from the top down, eh. When you coming back to wonderful Texas. Share this post Link to post Share on other sites
manholt Report post Posted March 25, 2016 Bill. I'm in wonderful TX.. I'm in Gladewater until tomorrow am, then at house in pm and I have a slew of stuff to take and do between Sunday am and Tuesday am before the Doctor puts me to sleep for 4-6 hours, Tuesday morning at 0830! Having all my teeth replaced by implants....I'll send a PM when I can laugh again, around 4/10 Carl Share this post Link to post Share on other sites
