Used one of those Affresh pods today. It's the second one I've used. Not entirely convinced it's achieving much but it was a nice day to have several gallons of hot water sloshing around in the house.
Last month I noticed just how crud filled the softener dispenser was, and there's no way to take it apart so I just had to sort of reach into the holes and do what I could, fill it with water and such and just shake it around trying to dislodge everything. Figured I should probably start cleaning the tub as well.
Citric acid can be a more useful alternative: easier to increase strength as it is a powder and doesn’t have much of a smell. It also a useful ingredient for making cheese sauces, ice cream and desserts.
I once moved into a flat in a hard water area and the toilet bowl was super gross from built up scale. Hearing the advice of using an acid to clean it, I tried vinegar and the like, but it was insufficient. The thing that finally shifted it was getting the water level really low (by vigorously using the toilet brush to effectively force the water round the U bend without having to flush) and shaking citric acid power liberally in the bowl. I let it sit for a while and it partially dissolved into the residual water coating the bowl (producing what must've been pretty concentrated). Then I gave it a flush and gave it a scrub with the toilet brush again and most of the stuff shifted. It was like a gross miracle
I only have experience with North American style residential toilets, no idea if this works with those high pressure commercial toilets or different ones from around the world, but...most toilets I've met, you can flush them by rapidly pouring a bucket of water into them, they'll flush, and then the bowl won't be refilled because the cistern mechanism hasn't gone off. So if you need an empty bowl that's a quick and easy way to achieve it.