Sludge in Holding Tank

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HarlenW

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My holding tank has some sludge in the bottom that I can't get out when pumping it out. It is a 40 gallon plastic tank on my 2006 Mainship with 700 hours on the engine. I used a formaldehyde based deodorizer for most of that time.

When the tank is pumped out as much as I can, there is about two inches of material remaining. I recently had the macerator replaced and the installer also said there was sludge in the tank, even though we had rinsed and pumped it out several times before he started work on it.

Any tips would be appreciated.

Also comments on these suggestions from a Google search:
- Place ice cubes in the tank and then take the boat out to loosen the sludge.
- Use water softener in a cleaning cycle to loosen the sludge adherence to the tank wall.

Thanks.
 
Make a water blaster out of PVC pipe to act like a "Butterworth Nozzle" and go into the tank and clean it while you are discharging the residue. To prevent, eat more roughage.
 
If there is no access hole in the top of the tank, install one. Use one of the six inch or so screw in deck plates with a rubber gasket.

Now, with the access plate open, use whatever seems appropriate to loosen the sludge. I used a harden hose & nozzle, a scraper, and a long handled toilet brush. You will have to pump it out a few times while you are cleaning it. I used a hand operated bilge pump, the kind that looks like a bicycle pump.

Two inches of sludge would seem like it would block the discharge opening. Remember, you can never pump it completely because the discharge port is on the side, not the bottom.

Two things you can do to minimize sludge buildup:
1. Use a biological, rather than chemical treatment. Odorloss and K.O. are two choices.

2. Rinse the tank after pumpout. Run water from a garden hose into the deck fitting with as much force as possible, then pump again. Don't use the same hose you use to fill your potable water tank.
 
i woudn't loose sleep over sludge in my holding tank.... but if it really bothers you then just pull the access plate (where your tank sender is likely to be) and blast the bottom with a hose nozle. holdign tanks usually dont' have any baffles so it's easy.

i dont' think the Ice cube thing will do much in a trawler! maybe in go fast...

replacing the macerator on a 4 year old boat, let me guess.... Par or Jabsco impeller pump?
 
quote:
Originally posted by PascalG

replacing the macerator on a 4 year old boat, let me guess.... Par or Jabsco impeller pump?

Click to expand...

Jabsco, and all four screws holding the damn thing together failed. The piping held it somewhat in place and we only had a little leakage.
 
With an "empty" tank, put in a quart (32 oz.) of Calgon water softener and between 5 and 10 gallons of water preferably hot. Go for a ride and allow the mixture to slosh around in the tank. That should dissolve pretty much everything. If you have a large enough vent, stick a garden hose in there to loosen the remainder. Pump out while the garden hose in doing its thing. It took me about 5 minutes of pumping until the site glass was flowing clear.

Install a Camco Tornado and flush the tank every time you pump. That should solve the recurrance.
 
quote:
Originally posted by PascalG

i woudn't loose sleep over sludge in my holding tank.... ......
Click to expand...


If I had 2 inches of sludge in the bottom of my tank I would not be able to remove the contents, it would be covering up the outlet nipples.

I cleaned my tank because I purchased a monitoring system that reads through the walls of the tank and it gives a false reading if the walls are caked in sludge (not a great system for a holding tank but fine for a water tank).

There's no reason to worry about sludge unless it is causing a problem.
 
quote:
Originally posted by HarlenW

quote:
Originally posted by PascalG

replacing the macerator on a 4 year old boat, let me guess.... Par or Jabsco impeller pump?

Click to expand...

Jabsco, and all four screws holding the damn thing together failed. The piping held it somewhat in place and we only had a little leakage.

Click to expand...


well, you're lucky it even lasted 4 years... you should have rplaced it with a Sealand, they can run dry and are nearly bulletproof. a little more money but well worth it
 
Pump out frequently and rinse with water. I fill half way with water after a pump out and pump out again. Most places will let you do this. Also take the boat for a ride prior to pumping out. If you plan on a short ride with the boat, put some water in the tank and run it. Then go back and pump it out. Little by little things will probably clear out. We live on the boat all Winter and don't have issues with this practice.
 
Ron the trick with the foil type monitors is installing them on the opposite side of the discharge hose. That is where the tank usually gets the coating causing you to recalibrate. It sure beats the in tank sendors that get stuck with crap.
I agree install a top 6" screw on cover for occasional cleaning. I prefer OderLess and every moth CP because it helps keep the sludge factor down over scenting the tank.
Pascal I agree the SeaLand pump is a far better option than the Par or Jabsco macerators.
Bill
 
quote:
Originally posted by Billylll

Ron the trick with the foil type monitors is installing them on the opposite side of the discharge hose. That is where the tank usually gets the coating causing you to recalibrate. It sure beats the in tank sendors that get stuck with crap.
Click to expand...

Thanks for the hint. I'll try that. The system I have doesn't allow "recalibration". I don't remember the brand off hand.

I'm thinking part of the problem may be related to the fact that the PO used baby oil on a regular basis in the head to lubricate the pump. Or it might not be, I can't prove it. I'll try moving the sensors.
 
Fill it full of clean water and hit some rough water, then pump out.
Repeat if necessary.
 
Thanks for all the good feedback, guys. And it was a Sealand that was installed, Pascal.

I say two inches of sludge because that is what I see in the bottom of the tank when I look at it but I can only see one side and it may be that the remaining liquid is tipped forward a bit at that point. I just figure that getting the sludge out increases the useable capacity a bit. Yeah, I know, a bit anal. [:-smirk]
 
quote:
Originally posted by HarlenW

Thanks for all the good feedback, guys. And it was a Sealand that was installed, Pascal.

I say two inches of sludge because that is what I see in the bottom of the tank when I look at it but I can only see one side and it may be that the remaining liquid is tipped forward a bit at that point. I just figure that getting the sludge out increases the useable capacity a bit. Yeah, I know, a bit anal. [:-smirk]
Click to expand...


Did you stick your finger in to measure it? ;)

Yes, depending on the tank, that could reduce capacity enough to matter.

You have been given several ideas to try, now it's time to get down to business.
 
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