Like many have said here: water is your best friend. Just solids won't break down and will pyramid . In my 29h the toilet is on the opposite side there is a second gate valve under the black tank which I keep closed. Otherwise the liquids would have to fill the crossover pipe before they stay in the tank to soften the solids. I fill the toilet with water (just like your home privy) after each flush. My gauges stay accurate and it dumps easily.
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