O aquarista verifica o pH e o cloro.

O is the masculine singular definite article, meaning the.

So O aquarista = the aquarist.

In Portuguese, it is very normal to use the definite article before a noun like this, including professions or roles, when you are talking about a specific person. English sometimes does this too, but Portuguese uses it more consistently.

Aquarista means aquarist — someone who takes care of aquariums or keeps fish and aquatic life.

Depending on context, it could refer to:

• a hobbyist
• a professional who maintains aquariums
• someone responsible for checking water conditions

So it is a person connected with aquarium care.

The noun aquarista can be used for both men and women. The article usually shows the gender:

• o aquarista = the male aquarist
• a aquarista = the female aquarist

This is common with some Portuguese nouns ending in -ista.

Verificar is the infinitive, meaning to verify / to check.

In the sentence, the verb is conjugated in the present tense for he/she/it (or you, formal):

• eu verifico = I check
• você / ele / ela verifica = you / he / she checks

Since the subject is O aquarista (the aquarist), Portuguese uses verifica.

Literally, yes, verifica comes from verificar, which can mean to verify.

But in a sentence like this, a more natural English translation is often:

• checks
• tests

So O aquarista verifica o pH e o cloro is often best understood as:

• The aquarist checks the pH and the chlorine.

That sounds more natural in English than verifies in this context.

Both o pH and o cloro are direct objects of the verb verifica, and here they are presented with the definite article:

• o pH = the pH
• o cloro = the chlorine

Portuguese often uses definite articles where English may or may not use them. In this sentence, the speaker is referring to specific water measurements/levels being checked.

Also, notice that the article is repeated before the second noun:

• o pH e o cloro

This is completely normal in Portuguese.

In this sentence, it is treated as masculine because it appears as o pH.

Abbreviations in Portuguese often take a grammatical gender by usage or convention. With pH, it is normal to say o pH in Brazilian Portuguese.

So you should learn it as:

• o pH

In Brazilian Portuguese, pH is usually read letter by letter:

• p = pê
• h = agá

So pH is pronounced approximately as:

pê agá

In the sentence:

• o pH → o pê agá

The word e means and.

In Brazilian Portuguese, e is often pronounced like ee when spoken in connected speech, especially before a consonant. Before a vowel, it may sound closer to i as well.

So in:

• o pH e o cloro

the e is commonly pronounced something like ee.

It is usually not pronounced like English ay.

Yes. This sentence follows the basic Subject + Verb + Object order:

• O aquarista = subject
• verifica = verb
• o pH e o cloro = objects

So it matches English quite closely:

• The aquarist checks the pH and the chlorine.

That makes this sentence structurally easy for English speakers.

Grammatically, Portuguese strongly prefers the article here.

• O aquarista verifica o pH e o cloro. = normal
• Aquarista verifica o pH e o cloro. = unusual in ordinary speech

Without the article, it may sound like:

• a headline
• a label
• a very reduced style

So for normal sentences, use o aquarista.

Cloro is simply the Portuguese word for chlorine.

It is a cognate, but Portuguese uses a different ending:

• English: chlorine
• Portuguese: cloro

This is very common between the two languages: related words often look similar, but not identical.

Yes. In practical context, that is often what it means.

A native speaker would usually understand this as checking:

• the pH level
• the chlorine level

Portuguese often does not need to spell out nível de pH or nível de cloro if the context already makes it obvious, such as aquarium maintenance.