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anacapaisland42 · 22-09-2015, 15:54

Suggest you put a grease trap under sink to intercept most of grease.
Bill

jeepbluetj · 22-09-2015, 16:29

From experience with grey waste in my rv: Lots of hot hot hot water + diswashing detergent. Then some acid (like vinegar)

I would not use bleach or lye.

**Wotname** · 23-09-2015, 01:45

Quote:

Originally Posted by Dockhead

……..

I thought about lye, but I suppose lye would wreck the Whale Gulper pump and/or the bilge pump type float switch in the system. Or would it?

Any other ideas?

……...

OK, a bit more time right now to post more!

First a disclaimer - I have never had a gray water tank on a boat but I have cleaned my share of grease traps and blocked drains on farms etc. I also not a chemist but have had some experience with acids and alkalis as part of a misspent youth

.

Lye - common product, also know as caustic soda or sodium hydroxide NaOH.

Unlikely to cause any problems with the Whale pump; this site ( Sodium Hydroxide : OSH Answers ) suggests the following as PPE - butyl rubber, natural rubber, neoprene rubber, nitrile rubber, polyethylene, polyvinyl chloride, Viton®, Viton®/butyl rubber, Barrier® (PE/PA/PE), Silver Shield/4H® (PE/EVAL/PE), Trellchem® HPS, Trellchem® VPS, Tychem® SL (Saranex™), Tychem® BR/LV, Tychem® Responder, Tychem® TK. - . I would expect the Whale components is likely to be one of these!

But caution is required with it's use. It attacks most (all?) metals, reacts violently with water and is strongly alkaline - it certainly burns skin.

Never the less, it is has been used by the common man since forever.

Stick it down the drain, and away goes all the fatty substances - they are converted to simple soaps. Of course, in the drain, it is out of sight and out of mind. The holding tank is another story.

Look up soap making with lye, IIRC one uses about 1/7 or 1/8 lye to fat by weight for basic soap. When fat and lye are converted into soap, the caustic aspects of lye no longer exists.

So back to the holding tank, guess the weight of the crud, carefully mix some lye (about 1/8 of guessed fat weight) with water and add to holding tank.

Assuming no violent reaction, go sailing to mix it all up. Next day, pump it out and chuck in some vinegar to neutralise any remaining lye.

Be brave and let us know if it works

Russ · 08-10-2015, 06:56

Don't know about Grey but works for Black

Fill tank half way with water add generous amount of Original Wisk detergent and go for a ride. Pump out. Repeat. Clean as whistle. Also can use Original TIDE POWDER (has silicone granules in it to scrub tank) Russ

**carstenb** · 08-10-2015, 07:28

Dockhead - vinegar is cheap. Dump a liter in every once in a while and I suspect your problems will disappear. I would be cautious using lye. It will turn to soap when mixed with fat, but hwat kind of soap? If it is a thin liquid - fine - if it gets chuncky fat - it will cause more problems.

senormechanico · 08-10-2015, 09:27

Quote:

Originally Posted by Wotname

A dedicated shower tank will still contain fat, body fats are removed with shower, that's why we use soap!

Does that mean that I can eat all I want and be skinny as long as I shower often?

**a64pilot** · 08-10-2015, 10:28

Quote:

Originally Posted by Russ

Don't know about Grey but works for Black

Fill tank half way with water add generous amount of Original Wisk detergent and go for a ride. Pump out. Repeat. Clean as whistle. Also can use Original TIDE POWDER (has silicone granules in it to scrub tank) Russ

Dishwashing machine powder works well too, it doesn't foam.
With powerboats that had oily bilges or any boat with bilge slime, just dump some in and forget about it, the bilges will self clean

**Dockhead** · 08-10-2015, 11:38

Thanks for all of the replies.

I bought some of the enzyme drain opener and will try that first when I get back to the boat.

Interesting tip about dishwasher powder and bilges -- I'll definitely try that too. I have very deep bilges + keel stepped mast = slimy bilges -- ick!

peghall · 08-10-2015, 11:45

Quote:

Originally Posted by a64pilot

Dishwashing machine powder works well too, it doesn't foam.
With powerboats that had oily bilges or any boat with bilge slime, just dump some in and forget about it, the bilges will self clean

No they won't. The detergent simply emulsifies the oil so it sinks instead of leaving an incriminating oily sheen on the water. Nor will that leave you with a clean bilge...any more than just pouring detergent into a sinkful of dirty greasy dishwater, swishing it around and then just pulling the plug will leave you with a clean sink.

Whether a bilge cleaner is environmentally friendly, or even"biodegradable" (a meaningless feel-good term intended to mislead you in believing it means the same thing as “environmentally friendly’…it doesn’t!) is immaterial because no cleaning product can magically turn the grease, oil and diesel in a bilge into an environmentally friendly mixture. Detergents and degreasers only emulsify petroleum products so that they sink instead of putting an oily sheen on the water when your bilge pumps dump it overboard. And it’s never ceased to amaze me that the same people who have spasms at the idea of pumping a little truly biodegradable toilet waste or gray water overboard think nothing of just dumping a "biodgradable" bilge cleaner into a bilge full of oily water and letting the bilge pumps send it overboard.

**a64pilot** · 08-10-2015, 11:58

I know that it emulsify's the oil, so does steam cleaning, and Simple Green etc. that is how and why it works, it in simple terms mixes the oil with the water.

Matter of fact if you wash your hands or your oily rags in soap, you emulsify the oil and grease too, so don't wash your hands?

How Detergents Work

So how do you clean any oil that may be in your bilges out? Even if you get on your hands and knees and clean it out with paper towels, what do you do with them?

Ever heard dilution is the solution for pollution? OK, so I'm not saying dilute millions of gallons of oil, but if I emulsify a tablespoon of oil from my bilges and pump it out, I'm not going to lose any sleep myself.
Now my bilge petroleum product wise is clean as a whistle now, but back in my powerboat days anyone who ran Two Stroke Detroit's that told you they didn't have a speck of oil in their bilges, never looked.

**Dockhead** · 08-10-2015, 12:47

Quote:

Originally Posted by peghall

No they won't. The detergent simply emulsifies the oil so it sinks instead of leaving an incriminating oily sheen on the water. Nor will that leave you with a clean bilge...any more than just pouring detergent into a sinkful of dirty greasy dishwater, swishing it around and then just pulling the plug will leave you with a clean sink.

Whether a bilge cleaner is environmentally friendly, or even"biodegradable" (a meaningless feel-good term intended to mislead you in believing it means the same thing as “environmentally friendly’…it doesn’t!) is immaterial because no cleaning product can magically turn the grease, oil and diesel in a bilge into an environmentally friendly mixture. Detergents and degreasers only emulsify petroleum products so that they sink instead of putting an oily sheen on the water when your bilge pumps dump it overboard. And it’s never ceased to amaze me that the same people who have spasms at the idea of pumping a little truly biodegradable toilet waste or gray water overboard think nothing of just dumping a "biodgradable" bilge cleaner into a bilge full of oily water and letting the bilge pumps send it overboard.

Relax; we're not talking about oily bilges.

My engine room has a separate bilge which I keep clean and dry. If anything gets into it, I pump it out with my oil change vacuum pump and dispose of it in the oily waste vat at the marina. Then I scrub it down with paper towels. I have a dripless shaft seal so it stays dry as a bone.

The dishwasher powder I would use in the main bilge, which gets rainwater in it from down the mast. Also drips from the reefer drains; sometimes a little overflow gray water, etc. But never oil.

**Wotname** · 08-10-2015, 19:14

FWIW, most but not all dishwasher powders and tablets are quite alkaline, some very so.

For a quick and dirty test, place a spoonful on a piece of Al foil and leave overnight in damp air.

I would be cautious about using any medium to strong alkali in the bilge - test first

**carstenb** · 08-10-2015, 23:41

Quote:

Originally Posted by senormechanico

Does that mean that I can eat all I want and be skinny as long as I shower often?

Well If you shower with a friend - there are interesting fringe benefits to be had, including exercising together

Juho · 09-10-2015, 00:05

For bilges I have used warm water, normal dishwashing liquid and dishwashing brush since I can reach most corners of the bilge manually. Dishwasher detergent (for dishwashing machines) is for me the next level of efficiency that is still quite harmless to the nature.