i just changed my thermostat and topped up my radiator, however i think i lost more antifreeze than i should have, i used a test strip and it didnt even change colour

so yeah the water was a pretty reddy browny dirty colour so im thinking it might need changing anyway, so wats the deal, ive seen cooling systems flushed before so i know its a pretty simple operation, im just wondering how much antifreeze and how much water the 20v is supposed to take,
mark said for his integra it was 2l of antifreeze with 3 litres of water, would my engine be about the same?
cheers for the help