Eco as in AA rated or something? It's still possible to wash nappies properly, you just have to make sure to rinse them enough. Do a rinse first with no spin to get them properly wet and nice and heavy (many machines base the amount of water they use on weight) or put a wet towel in the wash with them, then do a good long wash with extra water if you can (check your manual, some machines use extra water on a baby cycle or heavy soil, but some use less on these so you need to check your machine) and then enough rinses so that no bubbles are in the water and the nappies don't smell at all of detergent. For me with most detergents I need to do: rinse, long wash with anti allergy rinse, extra anti allergy rinse at the end.