Declorinăm apa înainte de schimbul de apă.

Declorinăm is the 1st person plural present tense form of a declorina = to dechlorinate.

So:

• eu declorinez = I dechlorinate
• noi declorinăm = we dechlorinate

In this sentence, Declorinăm apa... means We dechlorinate the water...

Romanian often uses the verb form by itself without the subject pronoun, because the ending already shows who is doing the action.

Because Romanian is a pro-drop language. That means subject pronouns are often omitted when the verb ending already makes the subject clear.

So:

• Declorinăm apa naturally means We dechlorinate the water
• Noi declorinăm apa is also possible, but it adds emphasis, like We are the ones who dechlorinate the water

Most of the time, Romanian prefers the version without noi.

Because apa means the water, while apă means just water.

Romanian usually puts the definite article at the end of the noun instead of using a separate word like English the.

So:

• apă = water
• apa = the water

That is why Declorinăm apa means We dechlorinate the water.

In schimbul de apă, the phrase means the water change or literally the change of water.

Here:

• schimbul = the change
• de apă = of water / water

Romanian often leaves the second noun indefinite in this kind of expression after de.

Compare:

• apa = the water
• schimbul de apă = the water change

So the first water is a specific thing being treated, while the second is part of a fixed noun phrase meaning water change.

Schimbul comes from schimb = change or exchange.

With the definite article attached:

• schimb = change
• schimbul = the change

So:

• schimbul de apă = the water change

In an aquarium or fishkeeping context, this is a very natural phrase for changing some of the water.

Înainte de means before.

It is a very common Romanian expression used before a noun phrase.

Examples:

• înainte de masă = before the meal
• înainte de plecare = before leaving / before departure
• înainte de schimbul de apă = before the water change

So the structure here is:

înainte de + noun phrase

If Romanian wants to say before someone does something with a full clause, it often uses a different structure, such as înainte să...

Because the two de words do different jobs.

• înainte de is a fixed expression meaning before
• schimbul de apă is a noun phrase meaning water change

So the sentence is built like this:

• înainte de = before
• schimbul de apă = the water change

Put together:

• înainte de schimbul de apă = before the water change

So even though de appears twice, it is perfectly normal Romanian.

The given word order is natural, but Romanian is fairly flexible.

Original:

• Declorinăm apa înainte de schimbul de apă.

Also natural:

• Înainte de schimbul de apă, declorinăm apa.

Both mean the same thing. The second version puts more focus on the time expression before the water change.

So yes, the sentence can be rearranged, especially for emphasis or style.

The letter ă is a very common Romanian vowel. It sounds like a short, relaxed uh sound, similar to the vowel in English sofa.

So:

• apă sounds roughly like AH-puh
• declorinăm ends with that same ă sound in the last syllable

This sound is important because a and ă are different vowels in Romanian.

It is a real Romanian verb, but it is more technical or context-specific than everyday verbs like a face or a merge.

You are especially likely to see a declorina in contexts like:

• aquarium care
• water treatment
• fishkeeping instructions

So it is perfectly correct, but it belongs to a more specialized vocabulary set.

Yes. Both are possible, but they are not exactly identical in feel.

• schimbul de apă = the water change
• schimbarea apei = the changing of the water / the water change

In aquarium contexts, schimbul de apă is very common and idiomatic.
Schimbarea apei is also understandable, but it can sound a little more like the action or process itself.

So the sentence as given sounds natural, especially in practical instructions.