Clean Black Tank without Hookup?

**EddieK82** · 07-29-2020, 10:00 AM

Hi,

We are at a campground where the we don't have a 3 point hookup. I would like to clean the black tank as it's registering 3/4 full after we drained it with the Honey Cart. They don't let you flush it into their Honey cart. Can I connect my hose and flush it out while it's closed just maybe clear the sensors? If not, what else can I try.

Also,

Any tips for keeping the tanks clean (Grey and Black) and running correctly where we don't have a waste tank on-site?

Thanks!

**geotex1** · 07-29-2020, 10:29 AM

I personally wouldn't worry about the sensors in this case. Just prep it after the dump with water and treatment of choice. You should get familiar with how to spot the black tank getting full - ala, flush burp - because black tank sensors are about as reliable as Whimpy paying for that hamburger... You can flush on your way out at the dump station or when home, if you have the ability to do so.

**EddieK82** · 07-29-2020, 10:33 AM

Originally Posted by geotex1

I personally wouldn't worry about the sensors in this case. Just prep it after the dump with water and treatment of choice. You should get familiar with how to spot the black tank getting full - ala, flush burp - because black tank sensors are about as reliable as Whimpy paying for that hamburger... You can flush on your way out at the dump station or when home, if you have the ability to do so.

What is flush burp? I'm not familiar with how to test the tank without sensors. Only our 2nd time out without a 3 point hookup. NVM, I just looked it up. Thanks for the info. I will remember this one.

**geotex1** · 07-29-2020, 10:41 AM

Originally Posted by EddieK82

What is flush burp? I'm not familiar with how to test the tank without sensors. Only our 2nd time out without a 3 point hookup.

So when a black tank is full, the venting is inhibited because there is limited to no headspace remaining. So when you flush the toilet when the tank is full and ready to dump, the surge of water causes air to burp up through the open toilet.

Black tank sensors are bad indicators at best. For instance, after 1 night here, my indicators said 3/4 full. Well, that was 5 days ago and I've not dumped.

**Houndbb** · 07-29-2020, 11:58 AM

Originally Posted by EddieK82

Hi,

We are at a campground where the we don't have a 3 point hookup. I would like to clean the black tank as it's registering 3/4 full after we drained it with the Honey Cart. They don't let you flush it into their Honey cart. Can I connect my hose and flush it out while it's closed just maybe clear the sensors? If not, what else can I try.

Also,

Any tips for keeping the tanks clean (Grey and Black) and running correctly where we don't have a waste tank on-site?

Thanks!

Eventually, you will come to learn how long (in days) you can go before dumping because the sensors are very unreliable, as @geotex1 said above. Even the grey sensors, which shouldn’t get gummed up are inaccurate. We use the Geo method (search online or here) to keep the tank relatively clean, it definitely keeps our bathroom odor-free.

I do have to ask, though, were you present for the pump-out? And is one of your valve handles located away from the main drain? If so, you may want to apply a label indicating that a 3rd valve pull is located elsewhere. On our first pump-out service, they didn’t know and we had to pay for another to use the kitchen sink. That wouldn’t affect your black tank/sensor however (no missing that pull).
N

**boyscout** · 07-29-2020, 01:45 PM

Originally Posted by EddieK82

Can I connect my hose and flush it out while it's closed just maybe clear the sensors? If not, what else can I try.

Does your trailer have a black tank flush inlet in a Nautilus panel? If so, that's what it's for. It's a separate system, not connected to your plumbing, that ends in a sprayer inside the black tank. It's frankly pretty rare that just running water into that will clean your sensors, but it might help.

There is a risk to running the black tank flush when the tank is closed. If you overfill the tank it will likely rupture, which is a messy and expensive problem to repair. However a lot of us use the black flush like this all the time; dump the tank, close it and partially refill with the black flush system, dump it again, repeat if necessary.

To avoid the risk I use a timer on my phone - 6-8 minutes - to make me remember to disconnect the black flush before it overfills the tank. Inexpensive gauges are available on Amazon that can be connected to your hose to measure the amount of water it's putting into your tank. Or instead you can take a hose into the bathroom and repeatedly fill and flush the toilet until you hear its tone change and it starts "burping" when you flush it.

Whichever approach you take to avoid overfilling it you then of course need the honey wagon again to dump the tank.

Originally Posted by EddieK82

Any tips for keeping the tanks clean (Grey and Black) and running correctly where we don't have a waste tank on-site?

Yes, do a search online for "GEO Method". There are commercial products that promise to clean tanks and keep sensors clean, but they are expensive and don't always do what they promise. Instead we use Dawn dish soap and water softener powder most of the time.

Immediately after dumping into the honey wagon put at least a cup of Dawn and a cup of water softener into the tank and add about five gallons of water. The next time you dump, or after a few dumps using the GEO Method after each, you may find that your sensors become more accurate again. A few people use Pinesol in their tanks. The idea is to get a good cleaning agent in there and give it lots of time to soak through the material that has collected in your tank.

However it's not just the cleaning agents, water is your friend for keeping tanks clean. ALWAYS have water in the tanks, and if your dumping schedule permits it then USE a lot of water when flushing, showering, etc. so the tanks are close to full when you dump.

Water is your friend. Do this with your gray tanks too; they will all be less trouble for you if you maintain them like this.

Good luck.

**xring100** · 07-30-2020, 08:33 AM

Originally Posted by boyscout

There is a risk to running the black tank flush when the tank is closed. If you overfill the tank it will likely rupture, which is a messy and expensive problem to repair. However a lot of us use the black flush like this all the time; dump the tank, close it and partially refill with the black flush system, dump it again, repeat if necessary.

The tank i still vented 100g the time it it wasn't you could only put a limited amount of water in the tank before the pressure equalized with the hose pressure and it would stop filling. Nothing inhibits the normal roof vent. The only risk here is that you end up over filling and pump some slightly poopy water up and out of your vent.

I have poured a cup of dawn dishsoap and simple green with 5 -7 gallons of hot water in the tank after flushig and emptying, then driven home this has worked for me

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**boyscout** · 07-30-2020, 10:36 AM

Originally Posted by xring100

The tank i still vented 100g the time it it wasn't you could only put a limited amount of water in the tank before the pressure equalized with the hose pressure and it would stop filling. Nothing inhibits the normal roof vent. The only risk here is that you end up over filling and pump some slightly poopy water up and out of your vent.

I'm interpreting around what your spell checker has done to your message above; hope I've got it right.

I personally know two people who have left their black flush running while they got distracted by something else and ruptured their tanks. One of them was lying under the tank with his arm wedged up the side of it when it blew. (He's still in psychotherapy.

) I've seen at least two other reports of it here in this forum from people I don't know.

So your assurances about pressure equalization and overflow out the roof vent are not reliable. It may work that way sometimes - in fact I've seen one report here about sewage flowing out the roof vent - but sometimes it doesn't. Therefore the best advice is not "don't worry about it, the laws of physics will protect you", but "be very cautious about overfilling the tank".

**xring100** · 07-30-2020, 10:43 AM

Originally Posted by boyscout

I'm interpreting around what your spell checker has done to your message above; hope I've got it right.

I personally know two people who have left their black flush running while they got distracted by something else and ruptured their tanks. One of them was lying under the tank with his arm wedged up the side of it when it blew. (He's still in psychotherapy.

) I've seen at least two other reports of it here in this forum from people I don't know.

So your assurances about pressure equalization and overflow out the roof vent are not reliable. It may work that way sometimes - in fact I've seen one report here about sewage flowing out the roof vent - but sometimes it doesn't. Therefore the best advice is not "don't worry about it, the laws of physics will protect you", but "be very cautious about overfilling the tank".

Oh man not sure how that could blow out in mine unless a turd or toilet paper floated up and plugged the roof vent which i guess theoretically possible. Or maybe they use a different kind of vent than what is in my 5th wheel.

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**xring100** · 07-30-2020, 11:57 AM

Originally Posted by boyscout

I'm interpreting around what your spell checker has done to your message above; hope I've got it right.

I personally know two people who have left their black flush running while they got distracted by something else and ruptured their tanks. One of them was lying under the tank with his arm wedged up the side of it when it blew. (He's still in psychotherapy.

) I've seen at least two other reports of it here in this forum from people I don't know.

So your assurances about pressure equalization and overflow out the roof vent are not reliable. It may work that way sometimes - in fact I've seen one report here about sewage flowing out the roof vent - but sometimes it doesn't. Therefore the best advice is not "don't worry about it, the laws of physics will protect you", but "be very cautious about overfilling the tank".

I did some looking after i read your post looks like you are absolutely correct. The campers tanks are so poorly designed and have zero margin to being full that that they can't even handle being pressurized to 3 or 4 psi the head pressure that would develop going 8-10 feet up the stack. As with everything else in the campers they are built around price price and price who cares if it works or if it will fail. Read stories of people having full tanks of water going down the road and having tanks blow out

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