If you live in the US you can buy these ingredients from lotioncrafter or theherbarie. If you are in the UK you can buy the ingredients from phoenixproducts.co.uk (they sell the EDTA and poly 20 but not germall), gracefruit (sells liquid germall plus and poly 20 but not EDTA).
91.9% Distilled Water (in the UK its expensive and hard to find so you can make do with purified from the chemist)
0.2% Tetrasodium EDTA
0.4% Liquid Germall Plus
4.5% Polysorbate 20
Heat the water and Tetrasodium EDTA to 80C. (Tetrasodium EDTA will help your preservative system.) Cool to 45C and add Liquid Germall Plus with stirring.
Mix the fragrance with the Polysorbate 20. Mix very well.
With stirring, add the fragrance/polysorbate 20 mixture to the water/Tetrasodium EDTA/Liquid Germall Plus.