|Imam Shafi, Imam Malik||Existence of water invalidates tayammum (but doesn't do so if water is available during the prayer)||Existence of water removes the prevailing purification that was achieved with earth
They also used the hadith of Hudhaifa(RA) which contains that words "in case water is not available" implying that as soon as water is found, this purification is terminated and removed.
They also used the tradition of Abu Said AlKhudri (RA) which states that the Prophet (SAW) said, "When you have found water, let it touch your skin."
The reason that it doesn't invalidate during prayer is based on the 47:33
|Imam Abu Hanifa, Imam Ahmad||Existence of water invalidates tayammum (wven if water becomes available during prayer, then also it invalidates)||Reasons are same as above.
The reason it breaks during prayer as well is because it is incompatible with the law to say that availability of something does not invalidate purification during prayer, but invalidates at other times.
|Group of Jurist||Tayammum is only invalidated from the occurrence of hadath||Existence of water negates the initiation of purification with earth
hadith of Hudhaifa(RA) means that when water is found, it is not valid to undertake this form of purification.