Installing Toilet and Tank Requirements

[Galion]

So I'm planning on doing some upgrading to my old trailer (1978 Scamper) by getting rid of the old recirculating style toilet and installing a new one along with a new black tank (since the toilet itself is the tank currently). Right now I'm thinking of going with a 21 gallon black tank along with a Dometic 310 toilet Found Here unless there are better recommendations. These are just my initial idea after doing a little researching online so I'm looking to hear from others their suggestions. I believe 21 gallons will be a good size, right now my trailer only has 10 gallons of fresh water which I plan on increasing to 20 and adding about a 10 gallon grey tank for the sink. If anyone can offer experience or ideas that would be great.

Thanks

[justafordguy]

The Dometic 310 and 320 series RV toilets are the best. We have upgraded both our trailers to these, so much better than the cheap ones the manufactures install.

[RDMueller]

21 gallons is probably not bad for the black tank. We have a 35 gallon black tank and with 3 people we can easily go more than a week without dumping. Now regarding the grey tank, I'd go bigger if you can. We fill our 35 gallon grey tank every couple of days even if not using the shower. Of course it depends on your usage. We do all of our dishes in the camper and that creates most of our grey water.