Holding tank needs deep clean

[BugOutBoat]

Our holding tank appears to have some build up. It has begun to leak out of the vent before our weekly pump out. We assume it has hardened build up. We have heard suggestions That we pump out And rinse a few times and then add Dawn soap and go sailing and shake things loose.

Is this the best process? If so, what exactly should this process look like? Is there a better/easier process?

 

[sail sfbay]

Do you have a mobile holding tank service where you are? I used BayGreen in the SF Bay to clean the holding tank on my Hunter 386 after it sat out of the water for 3 years. Below is their process.

During this process, your holding tank(s) will be pumped out on a first visit and the enzyme will be added. Next, the tank(s) will be filled about three quarters with water (please ensure you registered your tank sizes accurately with BayGreen to avoid potential overflow). The enzyme will sit in the tank for about a week (with your tank essentially full) before we return to remove it and flush the tank out with water.
The cost of this service is $159.00 for a tank under 40 gallons. For second tanks for service on the same date, $109.00 for under 40 gallons. Tanks larger than 40 gallons, please add $2 per gallon over 40.

This includes...
Initial pump out
Applying the enzyme
Filling your tank ¾ full with fresh water to activate the enzyme
Removal pumpout about a week later
Flushing the tank thoroughly to remove as much residue as possible

I am sure the head mistress has a cleaning method in her book entitled "Get Rid of Boat Odors", which you can purchase here.

Amazon.com: The New Get Rid of Boat Odors, 2nd Edition: A Boat Owner’s Guide to Marine Sanitation Systems and Other Sources of Aggravation and Odor eBook : Hall, Peggie: Kindle Store

Buy The New Get Rid of Boat Odors, 2nd Edition: A Boat Owner’s Guide to Marine Sanitation Systems and Other Sources of Aggravation and Odor: Read Kindle Store Reviews - Amazon.com

www.amazon.com

 

[Peggie Hall HeadMistress]

It's unlikely that any sludge has actually hardened unless the boat sat unused for at least a year without first flushing out the tank to remove any sludge--something that should always be done before winter or any extended layup)...If it has hardened, I don't know of anything that'll dissolve it. If it hasn't, there's a much less expensive way. If the buildup is only on the bottom, put 2-3 gallons of clean fresh water in it and flush an entire bottle (or container if it's the dry version) No-Flex into the tank. Let it sit for several days, then thoroughly flush out the tank with clean fresh water added through the deck pumpout fitting ('cuz that sends it into the tank at the bottom). To clean the sides of the tank, fill it completely with clean fresh water and add a container/bottle of No-Flex...let that sit for a few days and thoroughly rinse out the tank. Don't try to do both jobs at the same time...you need a stronger concentration of No-Flex to dissolve the sludge.

As for waste leaking out the vent, that can only happen when a tank is over-filled. You need a good tank level indicator. This is the one I recommend Scad Tank Monitors.

--Peggie