Is it permissible to perform ablution (wudu') and ritual bathing (ghusl) with pool or pond water whose taste has been altered by chlorine, and can it be measured against seawater, regarding which the Prophet (peace and blessings of Allah be upon him) said: "Its water is a purifier, and its dead are lawful"?

Scholars have differed regarding the validity of purification with water that has been mixed with a pure substance, which is not difficult to guard against, to the extent that it changes one of its characteristics.

If it is said that purification with it is permissible as long as the name "water" remains applicable to it, then there is no issue.

However, if it is said that purification with it is not permissible, then a distinction is made between it and seawater, for which there is a textual injunction permitting purification with it, because seawater remains in its original created state.

A distinction can also be made by saying that the change in seawater occurs with something that is impossible to guard the water against, unlike what was mentioned in the question.

Therefore, water that changes due to something impossible to guard against is pure (and purifies), and this is a great principle of the principles of purification.

As for the change in pond water due to something difficult to guard the water against, such as prolonged stagnation, algae, or tree leaves, it is pure (and purifies) according to the majority of scholars.