Cleaning Out Gray Water Tanks

[peghall]

Originally Posted by Dockhead

I'm thinking about trying some of these RV chemicals, like this: https://www.5starhappycamper.com/. I'd be curious to know what you think about it.

Those products are meant to deal only with human body waste...they're not formulated to emulsify cooking grease, body oils, hair, bits of food from pots, pans and plates, and all the other things that end up in a gray water tank. Save your money.

The tank is too small to have it pumped out, but it's not too small to dose with chemicals...which would do what that would be cheaper and easier to get rid of using a marina sanitary pumpout??? If they suck it out, the contents are gone...if you use a shop vac or whatever, you'd have to get rid of the contents AND clean out the shop vac or whatever.

So...if it were mine, I'd opt for the simplest, easiest solution: have it pumped out then use a pressure washer and detergent to clean out the EMPTY tank!

[ranger58sb]

Originally Posted by Dockhead

And that's a hot tip about RV stores. Yes, my boat has two plastic grey water tanks which take all grey water, including sink, shower, and washing machine discharge, and pump it overboard via Whale Gulper 220 pumps.

Originally Posted by Dockhead

I could, but since it only holds 20 liters or so, that's a bit of overkill.

How is a 20-liter gray water tank (or even 2x at 20-liters/each) at all useful for a boat with several people showering, eating (washing up), washing clothes, etc.?

And also, why have a grey water tank at all? Is it a requirement where you sail? (Apparently not everywhere, at least, since you also have overboard pumps.) If not required, wouldn't it maybe be simpler to eliminate it altogether?

-Chris

[a64pilot]

There are several chemicals specifically made for the grey water tanks, but dishwashing machine liquid works well too as it doesn't create suds. You can also toss a dishwashing machine tablet or two in the bilge every so often and it will keep it spotless. watch this link.

https://www.youtube.com/watch?v=gmdzFpdB--c

[Dockhead]

Originally Posted by ranger42c

How is a 20-liter gray water tank (or even 2x at 20-liters/each) at all useful for a boat with several people showering, eating (washing up), washing clothes, etc.?

And also, why have a grey water tank at all? Is it a requirement where you sail? (Apparently not everywhere, at least, since you also have overboard pumps.) If not required, wouldn't it maybe be simpler to eliminate it altogether?

-Chris

The tanks (there are two of them) are not intended for storage of gray water. They simply collect it for pumping overboard. The outlet is above the level of the fixtures, and the shower drains are below the waterline; hence the necessity of tanks.

[Fuss]

Originally Posted by ranger42c

How is a 20-liter gray water tank (or even 2x at 20-liters/each) at all useful for a boat with several people showering, eating (washing up), washing clothes, etc.?

And also, why have a grey water tank at all? Is it a requirement where you sail? (Apparently not everywhere, at least, since you also have overboard pumps.) If not required, wouldn't it maybe be simpler to eliminate it altogether?

-Chris

I think the 20l is a typo, more likely to be in the hundreds. Mine is 800l and is black water and grey water. I pump it out with a rheinstrom pump.
But anyway.... the solution is simple.

You run lots of fresh water into the empty tank at least once every 3 months. Flushing regularly is the answer. Use high quality detergent when washing up.

Sure, its dirty when you look in the tank, but it is not building layers of crud.

There is nearly no smell considering that everything is going in there.

I just replaced the pump diaphram recenty and there was nearly no smell and the reason was the flushing beforehand.

[a64pilot]

Most boats it's common to have a shower sump, but discharge the sinks directly overboard, this of course does lead to having more holes in the boat. I don't like holes in the boat myself.
I bet a regular shot of the dishwashing liquid would keep them cleaner

[rwidman]

I'm assuming the grey water tank already has some means of being emptied so why would a shop vac be needed?

Unless legally required, I agree with a couple others that the best solution is to eliminate the grey water tank if possible. On my boat the sinks are drained directly overboard, each with its own drain. Only the shower requires a pump (because it's below the waterline).

[Dockhead]

Originally Posted by peghall

Those products are meant to deal only with human body waste...they're not formulated to emulsify cooking grease, body oils, hair, bits of food from pots, pans and plates, and all the other things that end up in a gray water tank. Save your money.

The tank is too small to have it pumped out, but it's not too small to dose with chemicals...which would do what that would be cheaper and easier to get rid of using a marina sanitary pumpout??? If they suck it out, the contents are gone...if you use a shop vac or whatever, you'd have to get rid of the contents AND clean out the shop vac or whatever.

So...if it were mine, I'd opt for the simplest, easiest solution: have it pumped out then use a pressure washer and detergent to clean out the EMPTY tank!

But they say that they are for both gray and black water tanks? False advertising?

Well, your simplest easiest solution is similar to what i have been doing -- bail the tanks out into a bucket, and scrub clean. I wouldn't use a pressure washer, as that would put all the stinky carp into the air! It's such a disgusting job, I was hoping for some other method. LIke healthy bacteria or something else to dissolve the carp which collects there so it goes overboard.

[ontherocks83]

If the gross part is the smell spend the money and get a respirator. It might be a little over kill but anything to keep from throwing up right?

[Kenomac]

Our galley sink is connected immediately to a Gulper pump which discharges directly overboard. Are you sure your sink isn't hooked up the same way? Both bathroom sinks and showers drain into small grey water tanks which then discharge overboard via separate Gulper pumps.

[thinwater]

Originally Posted by Dockhead

I'm gradually getting my boat cleaned up after having lived on her since the end of April. A lot of cooking was done on board by a lot of different people, and I shudder to think what the grey water tank looks like. It will need to be cleaned out, which is simply the second most disgusting job on board.

Is there some other, less disgusting way to do it? Put hot water and dishwasher tabs down it? Pour Coca Cola down it? Some enzyme to break up and disperse the filthy, horrible, stinky deposits which build up in it? Anything at all, other than cleaning it out by hand???? I start to gag just thinking about doing this horrible job.

It seem like we have a failure to comunicate. Please correct me if I am wrong. I think most of the commenters (posibly me included) do not understand your situation.

Dockhead. My understanding is that you have a 20L tank that collects water from the showers and sinks. some food waste is included. From there, via a float-activated pump, the water is pumped overboard. The tank does not store water for pump out at a shore-side facility, it only serves as a sump for the transfer pump.

The reason it needs cleaned is either that it stinks (vent odor problem) or that the pump/float is acting up. Which is the reason it needs cleaned?

As for on-going odor problems, a sump that is dirty will never be a basket of fruit. How often is the boat used? I' guessing that if it were used continuously the water would not have time to get nasty. If the use is intermitant, yes, a head chemical such as Happy Camper (chemistry like Odorlos) should help, but it's not going to be a perfect solution. The truth is that grey water sumps are often poorly designed. If it was only shower water, the answer could be cleanliness. If food scraps are going in there, it's going to be more like a holding tank, and float/pump systems are going to require solid design and regular maintanace. Sorry.

Regarding the shop vac, I suggest the exaust hose be routed out a window, or you're going to blow stink into the cabin. better yet, a long sucction hose ad kep the vac on-deck.

[Dockhead]

Originally Posted by thinwater

It seem like we have a failure to comunicate. Please correct me if I am wrong. I think most of the commenters (posibly me included) do not understand your situation.

Dockhead. My understanding is that you have a 20L tank that collects water from the showers and sinks. some food waste is included. From there, via a float-activated pump, the water is pumped overboard. The tank does not store water for pump out at a shore-side facility, it only serves as a sump for the transfer pump.

The reason it needs cleaned is either that it stinks (vent odor problem) or that the pump/float is acting up. Which is the reason it needs cleaned?

As for on-going odor problems, a sump that is dirty will never be a basket of fruit. How often is the boat used? I' guessing that if it were used continuously the water would not have time to get nasty. If the use is intermitant, yes, a head chemical such as Happy Camper (chemistry like Odorlos) should help, but it's not going to be a perfect solution. The truth is that grey water sumps are often poorly designed. If it was only shower water, the answer could be cleanliness. If food scraps are going in there, it's going to be more like a holding tank, and float/pump systems are going to require solid design and regular maintanace. Sorry.

Regarding the shop vac, I suggest the exaust hose be routed out a window, or you're going to blow stink into the cabin. better yet, a long sucction hose ad kep the vac on-deck.

Yes, 20 liters, not 200.
Boat is in continuous use -- I have been living aboard since April.
Crap accumulates because solids settle out, or sludge forms, before the pump can suck it out and overboard.
There is no odor problem usually -- tank is vented to the outside.
It gets lots and lots of fresh water and dishsoap flushed through it.
Nevertheless, stinky crap accumulates.

Good tip about dishwasher tabs -- might put a couple of those in before the next time I sail in rough weather.

[ranger58sb]

Originally Posted by Dockhead

The tanks (there are two of them) are not intended for storage of gray water. They simply collect it for pumping overboard. The outlet is above the level of the fixtures, and the shower drains are below the waterline; hence the necessity of tanks.

Ah. Got it.

Our tiny shower sump is a similar "temporarily catch and pump-out" set-up.

The rest of our gray water drains directly overboard. I expect all our sources, with the exception of that show drain, are higher in the boat than yours are.

-Chris

[rwidman]

Originally Posted by Dockhead

............ Crap accumulates because solids settle out, or sludge forms, before the pump can suck it out and overboard.
There is no odor problem usually -- tank is vented to the outside.
It gets lots and lots of fresh water and dishsoap flushed through it.
Nevertheless, stinky crap accumulates..

Two thoughts (besides running the drains directly overboard, not to a sump):

1) Get a screen to put in the sink drain. This will catch food scraps which can be dumped in the garbage.

2) Connect a manual switch to the pump (leave the float switch connected as well) and empty the sump after each use. Rinse and empty with clean water if needed.

[scuba0_1]

We have a strainer that looks just like the ac strainer between out shower punk and over board. Our sink goes straight over. Get rid of the tanks.

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