How to clean the holding tank (black water)

[Presentation]

Ours is quite full of…..well,.. ..its hard to see the level of the black water even with a strong flashlight on the tanks top pointing down.

I have tried filling with clean water and rocking the boat. This did not work.

I added a quart of bleach plus some laundry detergent then filled with water and rocked the boat, let it sit for a few hours, rocked the boat more, emptied, refilled with fresh water 2x and its still very dirty. The water that comes out is pretty clean, its the tank inside sidewalls that remain dirty.

Basically I have crud on the inside walls of the holding tank.

Can anyone recommend a product to clean the inside of the holding tank?

 

[Turtlesboat]

Tide, poor in, fill with water, let it sit for a week.

 

[Newbie]

Somebody on here a year or so ago posted about something that you install in the top of the tank then hook a hose to it. It spins around and cleans the inside with a high pressure nozzle IIRC. I can never ever find what I'm looking for with the search function so maybe someone else will have better luck

 

[Lazy Daze]

The one I know about is made by Camco. Called the "tornado". I'm not sure about that other thread on this forum - maybe it's something else?

http://www.camco.net/Menu.cfm?SupCategoryId=10000&SubCategoryId=211&ProductId=2049

I would start by letting a cleaning solution sit in there for a week, as mentioned above. There might be "stuff" caked up on the interior wall, but I would venture a guess that the problem is more than likely due to staining.

 

[RollerCoastr]

The most common one is called the Tornado Tank Rinser.

The concept seems sound and the device is inexpensive, but I don't know anyone who has installed one.


(oops, too slow. Is there a way to delete a redundant post?)

 

[Lazy Daze]

(oops, too slow. Is there a way to delete a redundant post?)

I thought that only happened to me! :smt001

 

[cruiser]

I've filled the tanks about 1/4 the way with water, added some bleach then put about 3 bags of ice in the tank through the pump out deck fitting and went for a ride. After the ice melted I pumped out, repeated the process...when it was done it came out pretty clean.

 

[RollerCoastr]

Cruiser, I don't see how that's possible.

The hose attached to your deck fitting runs to the BOTTOM of your holding tank, and ice floats.

So wouldn't you have to jam cube by cube through the hose to get them into the tank? I would think that by the time you got to the end of the first bag, most of the cubes would already have melted.

 

[Presentation]

I picked up 1 24 oz jug of Lysol toilet bowl cleaner and 1 96 oz / three quart bottle of bleach.

This coming weekend we plan to run up to Fremont, about a 28 mile run, a cruise that combines rivers and lakes.

Before we return I plan to pour both into the tank via the deck fitting then run some water down as a chase then boat back to the marina and do a pump out.


This run will take several hours with the no wake zones. Likely we will also stop on the way back for lunch and fuel so the time my concoction will sit in the tank will likely be about 4 hours with periods of agitation and periods of little movement. Heck, I could easily add it to the tank earlier in the day and expand the time in the tank.

I’ll report back my findings.



If this does not work my next idea is to use hull cleaner.

If that does not work I may try miracid.

If that does not work I think I’ll give up.

 

[dpmulvey]

The Camco Tornado works great. Depending on the location of the tank, it may be an off season project. A fellow in ATL put one in his Sea Ray and put the hose connection outside the boat. Nice setup.

From Don Casey's column in BoatUS Magazine:

"How empty the tank becomes is a function of the location of the pump-out connection at the tank. If it is on the side, some residue is unavoidable. The best you can do is flush the tank to dilute what is left. If, however, the residue you are talking about is a solid mass at the bottom of the tank, try adding two cups of Calgon Water Softener (many supermarkets carry this) and a cup of liquid laundry detergent to two gallons of hot water, and pour this into the tank. Let this mix work for several hours, then fill the tank the rest of the way with fresh water. Pump it out the next day. Much of the now-emulsified waste should come out with the water. Rinse and pump again and you will have done about the best you can do."

Based on your predicament, I would up the up the mixture to match 1/3 to 1/2 the holding tank's capacity and after it has been sitting for a while, take the boat our for a ride to slosh the mixture around to get the rest of the tank, then pump out.

You may have to do this several times to make a dent in the problem. I would continue to put the Calgon and soap in the tank to preclude waste sticking to the walls once you get it clean.

 

[dpmulvey]

I picked up 1 24 oz jug of Lysol toilet bowl cleaner and 1 96 oz / three quart bottle of bleach.

This coming weekend we plan to run up to Fremont, about a 28 mile run, a cruise that combines rivers and lakes.

Before we return I plan to pour both into the tank via the deck fitting then run some water down as a chase then boat back to the marina and do a pump out.


This run will take several hours with the no wake zones. Likely we will also stop on the way back for lunch and fuel so the time my concoction will sit in the tank will likely be about 4 hours with periods of agitation and periods of little movement. Heck, I could easily add it to the tank earlier in the day and expand the time in the tank.

I’ll report back my findings.



If this does not work my next idea is to use hull cleaner.

If that does not work I may try miracid.

If that does not work I think I’ll give up.

NO! NO! NO! NO! NO! NO! NO! NO! NO! NO! NO! NO! NO!​

Lysol is a mixture containing soaps, phenols and cresols. The combination of Lysol (notably phenol) and bleach has been inadvertantly tried before -- and surprisingly, in the embalming industry. The deadly combination is cited in The Modern Embalmer, where James H. Bedino notes, "Bleach is not compatible with phenol and other phenolics, that are found in embalming rooms, and exothermic gas-generating reactions are possible."

For those of us that blissfully forgot their chemistry terms over time, an exothermic reaction is one that occurs when chemicals react, releasing heat. Sometimes lots of heat. Some explosions are exotherms.


This isn't to say that Lysol and bleach will blow up your boat. However, the strongest chemicals in the home are found in the kitchen, the bathroom and the garage -- and they're cleansers. It's no surprise that the majority of chemical burns and poisonings occur in those rooms. While the phenol/bleach combo isn't Mustard Gas, it's clearly dangerous.

Let me leave you with one thought: The R&D team at Lysol gets paid a ton of money to improve their product. If adding a little bleach to it would improve the product even a little, and do it safely, don't you think they'd be all over that already? :}

=================================================

The calgon and hot water is a safe and proven method.

From Bob Casey's column in BoatUS magazine:

"How empty the tank becomes is a function of the location of the pump-out connection at the tank. If it is on the side, some residue is unavoidable. The best you can do is flush the tank to dilute what is left. If, however, the residue you are talking about is a solid mass at the bottom of the tank, try adding two cups of Calgon Water Softener (many supermarkets carry this) and a cup of liquid laundry detergent to two gallons of hot water, and pour this into the tank. Let this mix work for several hours, then fill the tank the rest of the way with fresh water. Pump it out the next day. Much of the now-emulsified waste should come out with the water. Rinse and pump again and you will have done about the best you can do."

I would just up the ante to make the solution equal to about 1/3 to 1/2 the tank capacity and take your trip. You will probably have to do this more than once, but it does work. I had to do it on my Regal and was quite please with the results.

Good luck.

 

[Pseudomind]

I picked up 1 24 oz jug of Lysol toilet bowl cleaner and 1 96 oz / three quart bottle of bleach...

Are you sure it is safe to mix these in a confined area and then slosh them around for a few hours? I would try a couple of cups of Tide powder and fill the tank about half full, go slosh it around, come back and let is sit for about a week sloshing some more. Then pump out and see what happened.

 

[Presentation]

Well, the Lysol toilet bowl cleaner I purchased already has bleach. I was just going to add more.

Yesterday I did try a mixture of laundry detergent + about 2/3rds pint of bleach. The brand of laundry detergent was Tide HE.



You do have me reconsidering adding bleach. Hmm, I’m going to think about this.

 

[tdappleman]

Saw this thread - I was considering cleaning out my tank as well. Using the Tide HE is probably a good idea as it's low sudsing for the front loaders - already have some so may go add that to the tank.

 

[cruiser]

Cruiser, I don't see how that's possible.

The hose attached to your deck fitting runs to the BOTTOM of your holding tank, and ice floats.

So wouldn't you have to jam cube by cube through the hose to get them into the tank? I would think that by the time you got to the end of the first bag, most of the cubes would already have melted.

The fitting for mine is on the top of the tank.

 

[mwph]

Please do not mix chemicals. Ever. To clean anything. I have seen the severe problems, both short and long term, that can result.

 

[Four Suns]

The fitting for mine is on the top of the tank.

There is always someone who posts this whole ice BS... Even though the fitting is at the top of your tank, there is a drip tube that goes all the way to the bottom of your tank inside and has about 1/2" clearance between the tube and the tank bottom. Ice will not get into your tank that way... Plus... from the deck fitting to the holding tank, many times the run of the hose will go below the tank and go back up to connect to the top of the tank...

Ice can not make it into your tank from the pump out fitting...

I got a better idea. Flush the ice down your toilet so you can tear up all the rubber pieces between the toilet and the tank...

Geez...

Get some Domitec tank cleaner and fill it up with water and a couple jugs of that stuff... my tank still has white sides and there's been a lot of sh!t pumped through it... probably more than what has been pumped into the CSR forum.

 

[Four Suns]

I will also add that I've looked at that tornado do-dad thing. It's a good idea for a sump box... but it's a pretty low-quality device and I'm not too thrilled about drilling a hole in an expensive industrial don't-let-the-stink-out tank only to have odors seeping by that thing (or it breaking).

 

[wkearney99]

That and getting a proper seal on a polyethylene tank is difficult. You can't glue anything to it. There's only one rather expensive 2-part adhesive from 3M that sticks to it. The only decent way to get anything sealed to a poly tank is to have it spun welded onto it. But that usually requires taking the tank to a shop. Usually fittings (that aren't molded in) are into threaded sockets that were spun welded onto the tank. The tank walls are often too thin for enough threads to hold securely.

I have one of the Tornado units but never installed it due to lack of clearance for installing it (it stands taller than would fit). I might've tried but didn't have any luck finding a way to turn 90 degrees off the hose thread fitting within the clearance available. I agree that it's not high-quality construction. I'd be skeptical of how well it'd hold up to any sort of abuse, certainly not if you were attaching a hose directly to it each time. Maybe it'd hold up if you ran a length of hose off it to a more secure connection. But then you've got one more thing to leak and let the stink out.

 

[fresh water]

Scrub walls w ajax. Nice clean and easy.