We have an integrated Bosch dishwasher which has previously given
trouble - contents still dirty at the end of the wash. We had an
service guy round to look at it, and he diagnosed it as clogged-up
pipework; he showed me before cleaning it (yuk) and that did the job.
He advised routine use of those dishwasher-deep-clean detergents to stop
the gunk from building up again.

Unfortunately despite using the special cleaner, and being more rigorous
about pre-wash plate-scraping, the was has got quite bad again. So -
two queries:

1. Are all deep-clean agents equal? Eg, I've been using these things
from Sainsbury's, at 26p per clean: http://tinyurl.com/3emtbd

However, I recently saw some special stuff by Hagesan in a local
hardware shop at 6 quid a pop: http://tinyurl.com/455xom

Snake oil, or worth a pop?!

2. I find that the water in the sump at the end of the wash (on both
sides if the sump filter) is without fail very dirty. Presumably that's
what's just been used in the final rinse cycle isn't it? Shouldn't it be
pretty well completely clean?

Thanks
David