Inline ball valve between holding tank and macerator

[scgunner]

Mick,

I must be missing something here, isn't installing a ball valve with a full tank going to create the same mess as just replacing the macerator? And if do this you'll have an additional valve whose only purpose is to isolate the tank if the next pump fails and if the tank is full and if you can't find a pump out station.

It sounds like you're not the only one who doesn't have access to a pump out station which is surprising in these days of environmental awareness. And I'm really surprised to hear there are no pump outs in San Diego. I've got a pump out at my slip, there's one in the marina, one in the marina 30min away and there are two at my island of choice (Catalina) plus in Avalon there's a guy who will come out to your mooring to pump you out. That's why the need for a ball valve has never even occurred to me. I've changed that pump two or three times but I'd never attempt it before I'd pumped out the tank and flushed it with fresh water at least 5 times and even then it's not a fun job.

[Noah]

Kevin— There are lots of free pump-out locations in San Diego.

[scgunner]

Noah,

Yeah, I figured. Still doesn't explain Mick's reluctance to find one of those locations before starting the most horrible of jobs.

[Noah]

He may be on a cruise? Where I dock at SDYC, in the Shelter Island Yacht Basin, every sail, whether its in the Bay or going out to sea, I have to sail right past the Harbor Police dock, which has free pump-out and potable water 24/7.

[Mick Laver]

Yes, plenty of pumpouts in SD Bay, even one at the end of my dock at SGYC. I was at anchor at Glorietta Bay. Of course I pumped out when I got back to Shelter Island. Last time this happened was at Isthmus Cove, where the pumpout is located about 3 miles due north.

In both cases being able to isolate the holding tank from the macerator so I could swap in my spare macerator would have been beneficial.

[KWKloeber]

.

being able to isolate the holding tank from the macerator so I could swap in my spare macerator would have been beneficial.

Mick

Color me confused.  Op said you were looking to isolate the tank, and I explained that you can, indeed, do what you wanted. 
Have you now decided to stay "status quo"?

Cheers
Ken

[scgunner]

Mick,

So the pump failed once on anchor and once on a mooring, both cases you'd have to have a spare on board to take advantage of a shut off valve. That's a pretty expensive piece of kit to be carrying aboard for something that's not a real emergency. If you don't carry a spare you'll have to go get one which will likely put you in proximity to a pump out. I get it you want a shut off valve there so do it, your boat, your choice and all that. Even with a shut off valve you'll still have to deal with the mung in the pump, the hose to the pump, and the valve.

[KWKloeber]

you'll still have to deal with the mung in the pump, the hose to the pump, and the valve.

The valve should be placed at the pump inlet, not at the tank outlet.