Your website has been a brilliant resource for me. I have some questions if you could please advise me. 1. We have no definitive, exhaustive list of the attributes of tekhelet. Even if we have found a dye which fits the descriptions of chazal (of which some are quite ambiguous) that we do have, how can we be sure it is tekhelet without a mesoret or a ruling by the Mashiach himself? 2. Since at best we are in doubt as to whether we have the correct dye, the Tosefta Menachot 9:6 indicates that if it is the wrong color we have made the tzitzit pasul and we are therefore mevatel mitzvath aseh by wearing the begged. Is this not correct? 3. Finally some poskim (e.g. Rav Ben Tzion Abba Shaul) have expressed that wearing tekhelet would be motzi la’az al harishonim (since our parents have not worn tekhelet etc.). Why would you feel that this is not the case?