[jsb5717]

The rule of thumb for black tank usage is to never leave it open. Of course that's under normal use with an RV toilet. The danger is always having waste build up occur. When emptying a black tank you always want plenty of water in there so when you open to drain valve it empties more thoroughly.

With a standard toilet you will obviously have more water per flush so the risk of build up is likely reduced, however the principle is still the same. You're flushing into a tank, which is designed to hold and store material. Even with more water per flush the draining will be slowed by the tank. I wouldn't risk leaving the tank open even with a standard toilet. Seems like there are 3 options:

1. Leave tank valve closed and drain daily
2. Bypass tank for direct sewer attachment
3. Remove tank for direct sewer attachment

2 and 3 above will be determined by the placement of the tank and amount of space to allow for simply bypassing.

IMHO the Cons far out-way the Pros. I would advise against it. But if you're determined I also believe it's doable.