Diluimos la solución descalcificante, ya que hay cal.

Diluimos comes from the verb diluir.

For nosotros, diluimos can be:

• present tense: we dilute
• preterite: we diluted

So the form itself is ambiguous. You tell which tense it is from context.

In this sentence, it will usually be understood as present if the speaker is describing a procedure or a general action. But in the right context, it could also be preterite.

Also, it is diluimos, not diluemos, because diluir is an -uir verb. Its present forms are:

• diluyo
• diluyes
• diluye
• diluimos
• diluís
• diluyen

Spanish often leaves out subject pronouns because the verb ending already shows who the subject is.

So:

• Diluimos already means we dilute / we diluted
• adding nosotros is possible, but not necessary

You would normally only include nosotros for:

• emphasis
• contrast
• clarity

For example:

• Nosotros diluimos la solución, no ellos.

Without that kind of contrast, leaving it out sounds completely natural.

In Spanish, adjectives often come after the noun, especially when they classify the noun by type.

So:

• solución descalcificante = descaling solution

Here descalcificante is not just adding a personal opinion; it is identifying what kind of solution it is. That is why the post-noun position sounds natural.

This is very common in technical, scientific, and product-related language:

• producto limpiador
• agente desinfectante
• solución salina

Descalcificante means something like descaling or limescale-removing.

It comes from:

• des- = reversal/removal
• calcificar = to calcify / to form mineral deposits
• descalcificar = to remove scale or calcium deposits

So a solución descalcificante is a solution used to remove cal in the household-cleaning sense, especially from appliances, taps, kettles, coffee machines, etc.

In everyday Spain Spanish, you may also see:

• antical
• producto descalcificador
• limpiador antical

These are related, but descalcificante is perfectly natural, especially in product or instruction language.

Both ya que and porque can mean because, but they do not always feel exactly the same.

Ya que often sounds:

• a bit more explanatory
• a bit more formal or written
• close to since or as

So:

• Diluimos la solución descalcificante, ya que hay cal.

sounds like:

• We dilute the descaling solution, since there is limescale.

If you used porque, the sentence would still be correct:

• Diluimos la solución descalcificante porque hay cal.

But ya que gives a slightly more explanatory tone.

A comma is common before ya que when the second clause gives an explanation for the first one.

So the structure is:

• statement
• explanatory reason

That is why:

• Diluimos la solución descalcificante, ya que hay cal.

looks natural.

With porque, a comma is often not used when the reason is essential to the meaning:

• Lo hacemos porque hay cal.

So learners often notice this difference:

• ya que often appears with a comma
• porque often does not

That said, punctuation can vary somewhat with style and rhythm, but in your sentence the comma is very normal.

Hay means there is or there are. It comes from the verb haber.

You use hay to say that something exists or is present:

• Hay cal. = There is limescale.

You do not use está/están for that basic existence meaning. Estar is used more for location or state.

Compare:

• Hay cal en la cafetera. = There is limescale in the coffee machine.
• La cal está en el depósito. = The limescale is in the tank.

So in your sentence, hay is the correct choice because the speaker is saying that limescale is present.

Because cal is being used as an uncountable substance noun here, much like water, salt, or dust.

When Spanish talks about the presence of a substance in a general way, it often uses no article:

• Hay agua
• Hay polvo
• Hay cal

If you said hay la cal, it would sound like you were talking about some specific, already-identified limescale, which is not the normal idea here.

So hay cal means simply:

• limescale is present
• there is some limescale

In Spain Spanish, cal can mean different things depending on context, including lime in a chemical/material sense. But in household cleaning contexts, it very often means limescale or mineral buildup caused by hard water.

Because the sentence also mentions a solución descalcificante, the meaning here is clearly:

• limescale
• scale deposits

So a learner should not automatically translate cal the same way in every context. In this kind of sentence, it is best understood as limescale rather than the broader English word lime.