We have a 28BHS and find our grey water fills up so quickly it's becoming annoying. Our (seasonal) site has water and hydro hookup, but no sewer so we have to drain our tanks using our portable tote.
Since we are allowed to wash dishes outside, I've started using the outside shower to fill a plastic dishwashing bin and do my dishes outside, but I need to get a table that's adjustable to my height as the little one I currently have is so short it hurts my back.
But at least it's one way to save from filling up the grey water tank so quickly.
We do the euro-showers, wet, turn water off, soap up, turn water on and rinse off. Our children (age 3 and 7) have shallow baths, and usually only once a week as they swim so much and rinse off in the outside shower that they really don't need a bath more often than this. We may have to start walking to the public showers, which we can do but it's so much nicer to shower in our own shower.
For convenience, we wash our hands and brush our teeth (using a cup to save water) inside, which adds to our grey water.
Occasionally I wash the dishes inside (i.e. if it's pouring rain outside), but for the most part it's just washing hands, brushing teeth, quick showers (not daily) and baths once a week and we fill our grey tank usually daily.
Are the grey tanks on the 28BHS quite small?