There's a difference..
The Sodium Percarbonate has much more bleaching power vs just plain Borax..
This little piece, from another site, may be worth reading.
Washing Soda�Sodium Carbonate (Na2CO3) (Na = Sodium, water softening)
Sodium softens water by binding with Calcium and Magnesium forming solid, which can be rinsed off the fabric. �However, if not rinsed thoroughly, the minerals can redeposit onto the fabric and cause problems. �
Washing soda's PH is 11, very caustic (neutral PH is 7). Need to wear gloves to handle. �If not rinsed well, may cause skin irritation on baby's skin. �It doesn't dissolve in water as fast as baking soda, and its molecule is sharp, and can rub and damage thin fabrics. �Theoretically baking soda is sharp too, but since it dissolves in water so easily, it rarely damages fabric. �
Two things about washing soda that are great. �One, it has 2 sodium in its chemical formation, very effective in softening water. Two, it's very caustic (ph 11) so it's great in degreasing and removing stain.
Baking Soda�Sodium Bicarbonate (NaHCO3) �(notice: only half of Sodium as Washing Soda)
Baking Soda's PH is slightly base, not as alkaline as washing soda, so it doesn't cause skin irritation and you don't need gloves to handle them. It also dissolves faster in water than washing soda. �On the same token, since it's not as alkaline as Washing Soda, its stain removing power is not as effective. Also, since it only has one sodium in its chemical formation, its water softening power is half of washing soda's. �
Again, if it doesn't dissolve in water completely (don't see how that can be, unless you use way too much), it can rub and damage fabric. If you use baking soda in kitchen to scrub clean pots and stove top (super effective), you'll know exactly what I mean.�I think that's why BG discourages use of baking soda, although they should be more concerned about washing soda.
Borax�Sodium Borate (Na2B4O7·10H2O)
Contrarary to popular belief, borax doesn't soften water nearly as effectively as washing soda or even baking soda. �Look at the chemical formation. �Sodium is a tiny part of its formation. � When Borate (=Borax) is combined with a specific kind of acid, it softens water, but not on its own. Here's my source.�
Borax has great cleaning power though. That's why homemade detergent recipe always has this and washing soda. �Its PH is 9.5, pretty base and can remove stains. �It also breaks down into Hydrogen Peroxide (main ingredient in OxiClean), which behaves like, well, OxiClean! See Oxiclean for more details.
Oxiclean active ingredients: Something similar to Washing Soda + Hydrogen Peroxide H2O2
It's pretty much like Washing Soda + Hydrogen Peroxide. That's why homemade laundry detergent recipes always call for Washing Soda + Borax (which turns some water molecules to Hydrogen Peroxide). When Hydrogen Peroxide meets water, it breaks down into Oxygen and Water, forming little bubbles like soda. That's how it bleaches and cleans.
Vinegar
Vinegar use is controversial in the diaper washing world. �I read tons of links and my personal unscientific conclusion is, it depends on your water. Vinegar MAY react with some minerals in YOUR hard water. �So just give it a try in the final rinse cycle. �Part of the purpose is to neutralize the PH in water, especially when you have hard water and use alkaline detergents such as washing/baking soda and borax (and ALL of commercial power laundry detergents have some of them as the main ingredient, i'll explain more later). If you're not convinced you've not thoroughly rinsed off washing soda or borax, and worry that it'll irritate your baby's skin when wet, you can try white vinegar to neutralize these base molecules.
It's trial and error. �If you use vinegar and it causes funny things, stop. �If you don't use vinegar and you have problems, try it. �One thing I know for sure, if you add too much, it'll damage fabric (PUL is very fragile) and elastics. �That's just common sense though. �We all know vinegar dissolves things because it's acid.
Calgon (Ingredients? too long, check here)
Calgon is a non-precipitating (doesn't form solids) water conditioner and binds the minerals into a solution that does not redeposit on clothing or the inside of the washer. It must be added to both the wash water and the rinse water for highest effectiveness. It is more gentle to clothing and skin. It is also more expensive to use. I think it's the best water softening solution next to installing a water softener for your house. You don't need to worry about not washing your baking/soda clean, and nobody has claimed that Calgon damages their diaper.
What's the catch, you ask. Well, it's really really hard to find. I have to order online.
That's why I was thinking about a chemical analysis, to get a detailed breakdown...just a daydream, though.
