Not really new to RVing but not a real veteran yet. We purchased a used unit and are having trouble with the black tank filling up real quick. I do not think the tank is draining completely. I have tried to flush the tank with wand thru the toilet. My question would be what chemicals would be save to use and is bleach a good option to help break up hard deposits.My guess is the previous owner on their trips to Florida always stayed connected to sewer and did not let tanks fill.What should I or shouldn't I use? Thanks ahead of time dr3x

I would fill the tank with at least 5 gallons of water, wait for a day to let it soak in and then take a drive on a bumpy and curvy road several times. Some folks dump in a couple of bags of ice cubes to help break up stuff as it sloshes around.Dump to see if that helps... a clear hose attachment helps to see what comes out. You can get one online or at an RV supply store.An alternative (and will take longer) would be to fill the tank nearly full then dump in some Thetford Waste digester chemical. I prefer the powdered kind. Be sure to use the amount suggested based upon the size of your holding tank and maybe one extra envelope for good measure. Take a drive to slosh it around and then let it sit for a few days. Take another drive and then dump.Hit the bu

Maybe some hot soapy water and a drive. Really would not reccomend much more than that as it will be hard on seals. Also would reccomend a permanant sprinkler type flush kit be installed ASAP. Can you see anything through the toilot?

Bleach will do next to nothing to break up solids and scum in the tank. It's an oxidizer and disinfectant, but not really a cleaner in the traditional sense.Dishwasher detergent (not hand dish soap) would probably be the first thing I would try. Leave it in and drive around for a good while, preferably over curvy, bumpy, or hilly roads to get good agitation.

Oasisbob wrote:Maybe some hot soapy water and a drive. Really would not reccomend much more than that as it will be hard on seals. Since OP mentioned bleach, I assume you're talking about the effect of bleach on RV "seals".The only seals or gaskets in RV holding tanks are the blade valves and the toilet gasket. The blade valves probably use Santoprene which is unaffected by bleach. While a toilet gasket may be adversely affected by bleach, just avoid pouring bleach onto it or immediately flush the bleach off with water.

It takes time, but fill your tank and then add a a box of Rid-x, used for septic tanks. Rid-x is a yeast (an emzine) that's made to break down solids. The only problem is, it takes time to do it. So fill the tank and let it sit a week or so. The build up will begin to break down and then you'll be able to drain it out. You might have to repeat a few times to get it all out.You can also use an emzine eater for keeping drain pipes clean. In this case, I don't think you want a full tank of water, but enough to make the build up wet. The emzines will eat and dissolve the solids. Once soft, the solids will flush out.Bleach is OK for sanitizing, but you really want to flush it out and not sit. It will deteriorate your slide valves and rubber if left alone.

What chemicals to use | Good Sam Community

Veebyes
Explorer II
Nov 11, 2015
Since 2009 we must have cycled through ours hundreds of times of dumpings. After dumping the black, usually on the way out of the CG, we put a few gallons of water into the tank & off we go. The water sloshes around as we drive along disolving whatever might have been left in the tank for the next dumping.
TechWriter
Explorer
Nov 11, 2015
DutchmenSport wrote:
TechWriter wrote:
DutchmenSport wrote:
Bleach is OK for sanitizing, but you really want to flush it out and not sit. It will deteriorate your slide valves and rubber if left alone.

And you know this how?

Been there, done that on my first camper. That's how!

I suppose if you had an early 2000ish camper, it could have had polybutylene (PB) plumbing which bleach would have attacked.

Otherwise, it wasn't bleach that did in your first camper. Bleach won't harm RV plumbing (unless it's PB). RVs use ABS, PEX, Santoprene, and polyethylene -- none of which is affected by bleach. The only "seals" that may be affected by bleach are toilet ball valve gaskets.

BTW, I don't recommend bleach for cleaning OP's black tank or for using on a daily basis. Bleach won't break up old poo and it's not necessary to sanitize all that often.
BCSnob
Explorer
Nov 11, 2015
If Rid X really breaks down solids why does Rid X still indicate you'll have to have the solids pumped out of your septic tank periodically?:h
Wishbone51
Explorer
Nov 11, 2015
coolbreeze01 wrote:
Are you going by the gauge or actually looking down the commode with a flashlight?

That was my question... How do you know that it's full?
Dave_H_M
Explorer II
Nov 10, 2015
I you want to clean that tank out (if it needs it),go to wally word and get the wand that if flexible and has the whirling nozzles on the bottom.

Stick it in the tank thru the john seat and clean her out.

also you can search poop pyramid and get the same suggestion.

it will work, but is not as scientific as a bunch of the other home remedies.
B_O__Plenty
Explorer II
Nov 10, 2015
Pouring chemicals into a black tank is like a stinky guy loading himself up with cologne. Usually ends up smelling worse and doesn't do anything for the problem. Try flushing it with real hot water from your hose and lots of it. That might help break up the residue...

B.O.
2012Coleman
Explorer II
Nov 10, 2015
dr3x wrote:
Thank you to all that have taken the time to reply I think I will go with Geo method and repeat as needed.

Thank You All
Be sure to update with the results! No pictures needed though!
coolbreeze01
Explorer
Nov 10, 2015
Are you going by the gauge or actually looking down the commode with a flashlight?
DutchmenSport
Explorer
Nov 10, 2015
Don't loose track of the OP's original problem. He's asking how to clean the tank out, thinking there is a solid build up that not's washing out. He's not asking how to prevent it, he's asking how to remove it.
sdianel_-acct_c
Explorer
Nov 10, 2015
Ditto on Campa Chem that rockhillmanor said above for the black tank. You may need to use 2x the amount in hot weather. That's what we use. We use Scott toilet tissue that says RV Septic safe.
For the gray tank we use 1 cup of Dawn Platinum dish detergent and 1 cup of Borax dissolved in 2 cups of hot water.
No odors on either black or gray tank.

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