Just be careful if borax is one of the ingredients for the detergent, some manufacturers advise against it.
At the other end of the scale to what adrie recommends, you have those like myself who find that using the full dose of detergent leaves detergent residue in the nappies, which traps bacteria and can cause stinkiness, rash and loss of absorbency. It depends on lots of factors like water type (although we have quite hard water here so
it's not the case that hard water automatically means you need to use loads of detergent) and your washing machine so it's best just to try it and see. I would advocate starting with less since nappies that aren't properly clean will smell and look dirty as soon as you remove them from the machine so it's very easy to see that you didn't use enough detergent and just put them back in to fix the problem. Detergent build up takes longer to detect as it takes a while to build up to detectable levels and then requires strip washing to get it out and start afresh. Most nappy manufacturers say to use less than the full dose of detergent so make of that what you will! The ideas of minerals being redeposited in extra rinses is something I have never come across in 5 years of reading about cloth (and 4.5 years of using them while living with hard water) and being a member of lots of nappy communities including the nappy library network in the UK. If you're concerned about that, perhaps ask Bummis - they write a lot of good stuff about laundering nappies
Detergent is for cleaning and water softener like calgon and borax is for softening the water to prevent mineral build up on your diapers. Mineral buildup does exist ( I would suggest looking into it if you cloth diaper). It can cause repelling and rashes as well, since it is inhibiting the detergent from being able to do its job.
I am part of some no-nonsense diaper communities and I have never had to strip my diapers 7 months in.
How many times have you had to strip your diapers?
Needed to strip nappies rather than as general maintenance? Twice, I think, when I first started out and was using the full dose of detergent before people in here helped me work out the problem. In nearly 5 years of washing nappies.
Have you looked into the temperature at which water deposits are actually released as solids into the water? Do you have limescale on your hair (presumably washed at fairly cool temps) or just in your kettle (very hot temps)? Repeated rinsing does not cause hard water deposits to be left in nappies as the water isn't hot enough to cause the deposits to be released.
You claim that nappy detergents are made to rip people off but you seem to think that commercial detergent manufacturers are there for the good of mankind. No! They want you to use loads and therefore buy more, they want your clothes to smell lovely so you move, get a whiff and think, "Oooh this Persil smells divine and the lovely fresh fragrance must mean my clothes/towels/nappies are hygienically clean so I will continue buying this brand". Having spoken to many people who work in the cloth nappy world, I am confident in saying that those who make products for nappies are far more likely to have the best interests of the consumer at heart than the standard detergent manufacturers. Most who make nappy detergent are cloth users themselves who want to help others get it right.
I would suggest that the difference between UK and US machines might account for some of the information you're giving out that is most certainly incorrect for those in the UK. Machines here are mostly what you would call HE front loaders in the US. They don't use much water. Perhaps using a full dose of detergent with minimal rinsing works for you but it absolutely doesn't for many in the UK. Whether you agree with the facts or not, based on your 7 months of using cloth nappies, doesn't change the facts that people in the UK often start out using a full dose of detergent and encounter difficulties.
I'd really encourage you have a good look through the Bummis blog. They have a great post on laundry science. They know what they're talking about. I don't always agree with them based on personal experience but I can see the science behind what they say. If you'd care to share any science behind any of what you say, I'd love to read it.
If anybody in the UK has doubts about their wash routine, I'd recommend getting in touch with your local nappy library. They'll have a good idea what your water is like and how different detergents work in it.
ETA - Detergents generally contain water softeners anyway so if your water isn't particularly hard, you will be fine without it. If you do want to use it, look into your options. Borax isn't advised for nappies, nor is it widely available in the UK and Calgon is very over-priced. I think it was Which? who checked the numbers and found that when you take into account the price of buying it, you'd be better letting the limescale 'destroy' your machine over a long (long long) time and just buying a new machine with the money you saved on Calgon
. Supermarkets' own stuff works fine for me.