The GLDA is sold in three different forms a powder, a 38% solution and a 47% solution. The powder is hygroscopic so be careful to store it carefully if you end up with this version. In my day job I have used this product (the 47% solution) in replacing EDTA in household and industrial cleaning products and it worked very well. So there should be no reason that it wouldn't work in soap. @SaltedFig I'm not sure who you spoke to but the distributor for the Dissolvine brand in Australia is IMCD. They will generally only sell in large volumes but they might be able to point you in the direction of someone who is willing to resell the product in smaller lots. Alternatively you could approach one of the soap suppliers and ask them to get in some for a trial.