Is it permissible to perform ablution with alkaline water? May Allah reward you.

If alkaline water has not changed in taste, color, or smell, and its use does not result in harm, then ablution with it is permissible. However, if one of its properties clearly changes, it is considered pure (طاهر) but not purifying (غير مطهر) water, meaning it does not remove ritual impurity (لا يرفع الحدث), and it is not valid for purification according to the majority of scholars. The same applies if it causes harm to the body.