Waste tank sucked in

Glenny

Hi Everyone I have a question regarding my waste / grey tank. It was pumped out last year and everything was good. We have used it for 4 weekends and got a pump out before our trip this last long weekend. After the pump out we used it for 4 days and went from simcoe to the severn and back. When we arrived on Sunday to close up I looked in the engine bay and the tank was completely sucked in. I checked the 5/8 vent line and it blew through. Any ideas? If I have to replace the tank I don’t want to see this happen again. 

Thanks.

aero3113

Seems like the suction at pump out station was very high and the vent line couldn’t keep up or it was blocked. You can install a vent valve to prevent it from happening. I installed one in my old 242 and on my 330 when I bought it.

Glenny

Oh that circle with black and white is an extra vent? If so that makes complete sense. Pump out hose is a lot bigger then the standard 5/8 vent so it could never keep up to the suction if very high.

Aqua_Aura

@aero3113 do you have a link to that vent? 

Pat310

I installed the same one 2 years ago. Got mine on Ebay 
Dometic SeaLand 313255247 TankSaver Holding Tank Relief Valve 1-1/2 Inch
https://www.ebay.com/itm/223359211252

Glenny

Yes a link would be great I been trying to look for it.

Willhound

I changed out my tank a few years ago and the Dometic tank came with that valve.

aero3113

https://ardemco.com/accessories/sealand-dometic-313255247-tanksaver-holding-tank-relief-valve/

Black_Diamond

++ on that tank vent. Easy install. 

mattie

@Glenny that pic is some graphic content! Should be a warning on the thread.

lol

Aqua_Aura

I'll have to add that to my parts shelf, I am getting low on boat parts to install 😂

YYZRC

Make sure your tank is empty before you cut the hole for the relief valve.  Fishing the disc out of the tank is no fun 

Aqua_Aura

I think I still have the visions of aero cleaning the sludge from his tank when he did his 🤢

YYZRC

Yeah, he posted a few too many pics of that. 

aero3113

LoL! I can post again if the new guys want 😂

Grahamu

With a vacuflush system and no relief valve turn off the water supply and hold down the pedal to open the clamshell or put a round stick in to hold it open while being pumped out. This allows more air into the top of the tank.

Glenny

Mattie sorry there was no disclosure!! I had some graphic words when I seen it! 

Thanks Grahamu wish you were at the marina when I went for the pump out. I didn’t think to ask any suggestions I know last year it was pumped out fine without opening the toilet valve. 

Willhound

You're really going to be pi$$ed when you learn a new tank is $400 to $700 and that's before installation. 

Glenny

Yes I looked into it, that’s about the ball park figure.

Grahamu

@Glenny this weather sucks coming back early, probably Friday afternoon

PickleRick

700, that's almost as much as a new c-head or natures head composting toilet.  

I don't know about you guys but I'm kinda tired of pumping poo and having poo related issues.  This winter I'm going to seriously consider the conversion and turn the area where the waste tank sits into below deck battery storage for stereo and now thruster batteries.


I live in the sticks with lots of wooded area.  It's makes more sense for me to dispose of compost than it is to dump waste into my septic tank. 

Liberty44140

I would never consider getting rid of the tank because of resale. Surveyor will rip it apart. I am jealous though of you salty guys who can dump offshore. 

YYZRC

Reinflate the tank and see what condition it is in. Maybe you can have it welded if it’s cracked at all. 

Aqua_Aura

Hadn't thought about vacuflush vs manual? I have the manual pump so I assume in addition to the vent it is also able to get plenty of air through the toilet line? 

PickleRick

Liberty44140 said:

I would never consider getting rid of the tank because of resale. Surveyor will rip it apart. I am jealous though of you salty guys who can dump offshore. 

I would keep the old components.  Reinstall would be easy and the new buyer would certainly appreciate seeing all clean components along with new hoses installed before he/she took possession.

Im sure a smelly holding tank and permiated hoses have cost many a sale of a boat. Usually not a deal breaker for the cap'n but most admirals won't put up with that kind of lingering odor.

Glenny

So came back this weekend and the tank has gone back to its proper shape. I had cleaned around the tank prior to the start of the season and their are no leaks so I dodged the worse. I am ordering a tank saver as was posted in the link and will install so this won’t happen again. Thanks everyone once again for the input.

aero3113

WoW, that’s crazy it went back to the correct shape!!

mattie

@Glenny
Glad to hear you may have saved your original waste tank.

I'd probably do the tank saver for sure, replace the vent line & even the thru hull vent. 
Then add/replace the in line waste tank vent filter.

https://bigorangefilter.com/

Big Orange waste filters have a built in bypass vent as well. They howl during pumpouts.

kordo

I also have the tank saver and to be extra careful, I ask the pump out staff to use suction at half power.  At half power, it's still enough to completely empty the tank.  I also open the engine compartment hatch and keep an eye on the tank, thinking that if I see it start to collapse, I can tell the pump out staff to stop.  I had to replace my tank due to it collapsing a couple years ago.  Not a fun job.  

mattie

ALSO: most of the vacuflush toilets have a foot pedal lock.
Ball is to be fully open during pumpout. This allows for full dicharge of the vacuum holding tank in addition to the waste tank.

Not to sound authoritative here - but, it's in the Dometic manual.

LaRea

Wow, I learned a thing today:  I learned that I need to download a manual for my vacuflush toilet!