Equalize black and grey tanks

[EA37TS]

In days past some parks and campgrounds had "French Drains" where you were allowed to dump the grey tank. Nowadays the "French Drains" have gone by the way side and you can no longer dump waste (black or grey) directly on the ground in most, if not all, states. This removes the requirement or need for separate tanks.

My concern is those manufacturers that build an RV where the black and grey total capacity is less than the capacity of the fresh water tank.

[Chance]

Originally Posted by Ag&Au

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Personally I do not like the idea of allowing black tank matter to enter the grey tank for any reason. My main concern is the shower floor drain that is very close to the grey tank both in proximity and length of plumbing. If the grey tank does overfill for any reason (for instance a sink faucet failing or accidentally left open. I do not want fecal matter entering the shower floor and then possibly overflowing to the rest of the RV floor. The earlier idea of just allowing the black tank valve to open slightly is of no help, because turds are water soluble and liquefy readily. If you don't believe me, capture one and place in a glass of water.

For these reasons I would not buy an RV with one tank.

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Ken

Ken, I was thinking about this concern, and also Dave's above, regarding what it would take to make me feel comfortable that overflowing the tank would be next to impossible.

For me personally, a reliable emergency high-level switch in the tank that would turn off the incoming water line and also prevent the onboard water pump from running would do it. If the tank gets too full, just cut off all sources of additional water that could end up in black/grey combo holding tank.

This would be inexpensive, requiring at most only an switch, a water solenoid valve, and some control wiring.

The emergency tank level would have to be set low enough to accommodate any water that could be left in a sink, bathtub, etc.

[Scintor]

I solved this issue and abandoned the 3" stinky-slinky hose at the same time by switching over to Sewer Solution. As a function of its design I don't have to save grey water to flush out the hose following a black tank dump. My grey tank drains continuously throughout my stay, so I never worry about the grey tank filling up. Also, I no longer have to fight the 3" hose. Instead, I work with a much more manageable 1" hose that is washed out with clean water during the black tank dumping process. Finally, due to its smaller size, I am able to store all of the Sewer Solution pieces right in the wet bay between uses.

[Metalman]

Scintor,

Does it take much longer to drain the black water through a one inch hose than using a three inch hose?

[Scintor]

No, Metalman, it drains the black tank just as quickly as it drained using the 3" stinky-slinky hose. By design, the clean water that is used to macerate the contents of the black tank so it can pass through the 1" hose also speeds up the dumping process. I'm no expert, but I believe this is due to Bernoulli's principle which is employed during the maceration step. I use a Y-connector at the water source (immediately after a water filter) to simplify the connection of water to the coach and to the Sewer Solution. Others I've met, who also use Sewer Solution, use a quick disconnect at the hose(s) to make the whole set-up/take-down portion easier.

[EA37TS]

Check out this review before buying a sewer solution. It is not as great as one would lead you to believe. Sewer solution starts at about the 5 minute mark.

https://www.youtube.com/watch?v=dfTd0Slt_cU

[Ag&Au]

Originally Posted by Scintor

No, Metalman, it drains the black tank just as quickly as it drained using the 3" stinky-slinky hose. By design, the clean water that is used to macerate the contents of the black tank so it can pass through the 1" hose also speeds up the dumping process. I'm no expert, but I believe this is due to Bernoulli's principle which is employed during the maceration step. I use a Y-connector at the water source (immediately after a water filter) to simplify the connection of water to the coach and to the Sewer Solution. Others I've met, who also use Sewer Solution, use a quick disconnect at the hose(s) to make the whole set-up/take-down portion easier.

I have used a Sewer Solution for many years and have been very pleased with it. I have quick disconnects on all my water hoses and fresh water add ons (such as pressure regulator and external filter). I have 4 way splitters with individual shut offs on each leg. I install one directly to the site faucet. Why 4 way? Because I got a great deal on a couple of them. I keep an entirely separate hose for the sewer solution water supply and it is green so I never accidentally interchange it with one of my white potable water hoses. Of course, I also carry a slinky type sewer hose in case I have to dump where there is not water faucet available. I also have 40 feet of the dump hose available if I have to dump a long distance. I use it all when dumping into my sewer clean out at home.

Ken

[Metalman]

When I return home after a trip, before I dump the black water tank, I run a hose into the bathroom and add water through the toilet until the black tank is filled. Then I drain the black water tank and then the gray water tank. Occasionally I fill the black water tank again with the hose through the toilet to give it an additional rinsing.

Also, driving for several miles with the black tank partially filled tends to break up the solids into smaller bits that wash out better than the large chunks. I don't know if the chemicals I use to help eliminate odors tend to dissolved the paper and other solids.

[Scintor]

I've watched these tank flushing evaluations, too, and have no arguments with his results, however I did not buy the Sewer Solution for its tank cleaning properties. I bought it to make draining of the black tank easier which it does in spades. My coach has a built-in black tank flusher which does that job adequately on its own. I use the Sewer Solution to drain the black tank, then I flush out the tank using the built-in tank flusher and finish with another draining of the tank. I repeat the flush'n'drain cycle until the water is clear enough to meet my standard for a clean black tank. I built a custom hose and y-connection system to facilitate making this flush'n'drain process into one that is semi-automatic.