What is the ruling on purifying oneself with water exposed to the sun?

The Shaykh : Before I finish with what came to mind regarding the answer to your question, I want to remind you of something that is beneficial from a scholarly perspective. Since these solar water heaters have become widespread in the country, there has been a lot of questioning: Is it permissible to use this water that the sun’s rays heat up? Is it permissible to use this water? Because this is called "sun-exposed water," and many people have reached us who issued rulings that it is not permissible. Why? Because they relied on the hadith . We praise Allah, Blessed and Exalted is He, for having taught us something of the knowledge of hadith, which enables us to distinguish the authentic from the weak among the hadiths. And as part of this, we learned that this hadith is fabricated and has no basis. We used to be amazed at some scholars who have jurisprudence but no knowledge of hadith; they stop at this hadith and ask, "Why did the Messenger forbid sun-exposed water?" You hear very strange explanations. I say, "Praise be to Allah who has spared us," and I say, "This dead man does not deserve this condolence." Some of them say, "This prohibition is specific to copper vessels. Why? They say, 'Because the water that heats up in these copper vessels causes a very fine substance to dissolve from the copper, so if one performs ablution or bathes with this water, it may harm him, unlike if it were from another metal.'" Philosophies from which Allah has spared us by teaching us that this sun-exposed water is a blessing from Allah, Blessed and Exalted is He, especially in the way science has reached in this era. You find the water without any cost except the initial cost, which is the price of the work that the brother, for example, performs, then connects and installs it, and so on. And then a person finds that even in winter, on this cold day, if there is bright sun shining on the face of the earth, you find the water as if it is boiled. And all of this is by the grace and mercy of Allah, Mighty and Majestic. Therefore, this work that you are doing, in terms of its nature, is beneficial to people. And in terms of your continued engagement in it, I have clarified the path for you. And you have known, so adhere to it. Yes.