This doesnt quite make sense to me. we are talking about the colour of the lemon juice and the mms with no water arent we. Now there is a limit of the amount of ClO2 that could be released so when you dilute the reddish coloured mixture with water is this going to have a hint of yellow or red to it. How much of the available ClO2 is released in each case. 100 liters seems a lot to dilute a very small amount of mms and lemon juice. Remember student99 said it turned red everytime
so even with 1 drop of mms and five of lemon it would've turned red