Tap water in aquariums: what if we stopped being afraid of it?

Can tap water be used in aquariums? Chlorine, nitrates, pollutants, hardness, iron, plants... A sincere and nuanced feedback to make peace with everyday water.
Without dogma, without excessive chemistry, and with a bit of common sense.

 

No aquarium without water.

Yes, but which one?

 

I see myself, very young, on my bike, unable to keep balance because of the osmosis water bottle hanging on the luggage rack!
This osmosis water... the Grail that all manuals talked about. The absolute condition to obtain that soft and acidic water preferred by the Amazonian fish that made me dream with their colors.

Then, having become a killiphile, here I am squandering my pocket money on bottles of Volvic, reputed to be the least mineralized bottled water.

 

Because I lived in a large plain region with a limestone subsoil.
The tap water was hard, and for us aquarists, it was a curse we bore like a cross.

In short, we had hard water from the tap (like almost the entire country) and aquaristics, on the other hand, seemed to require soft and acidic water!

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Chlorine: a real problem... but often overestimated

Tap water, beyond its hardness (common to about 70% of the territory), also raises the question of chlorine, added in various forms to prevent or even eliminate bacterial and viral contaminations.

The solution is known:
Generally, it is enough to wait 24 hours (a totally arbitrary duration) for it to be considered suitable for use.

It is probably less if stirred, and especially if a diffuser is placed in it.
And it is probably even more so if aiming for absolute zero-chlorine.

Moreover, the chlorine level varies greatly depending on the periods and the risks perceived by health authorities, or even security ones (fears of biological attacks, for example).

 

So, one day is an estimated time by guesswork to declare that the water has gotten rid of "quite a bit" of chlorine.

But in reality, chlorine only poses a serious problem if it is present in large quantities.
Otherwise, organisms tolerate it more or less.

👉 A day of degassing... and we'll roughly consider it good!

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Nitrates: a problem for some, an opportunity for others

Nowadays, tap water also suffers from a tarnished image for other reasons.

The presence of nitrates, first.

Personally, having few fish and many plants, I am glad about it.
Nitrates are the basic food for plants.
Algae too, of course… but you don’t get something for nothing!

Anyway, no use fighting (except with your ballots):
👉 you will not remove them from the water.
Without plants, they will remain.
With plants, they will disappear.

 

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Modern pollutants: nothing new under the sun

Today, we discover a host of other more or less toxic molecules:
pesticide metabolites, drug residues, industrial effluents…

They were probably already there before, but now, we are aware of them.

I knew DDT, then Lindane, Atrazine, etc.
👉 Water from the past probably had nothing to envy from today’s water.

Let’s say, once again, there’s not much you can do about it.

Osmosed water contains very little, since everything has been removed.
But they also removed useful minerals, because no one really knows how to sort them out.

In short, I think we have to deal with it, keeping in mind that bottled water is not without its faults either (see recent news), not to mention microplastics from packaging.

 

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One last point about tap water: iron

One last important point:
👉 tap water no longer contains iron.

To avoid rust color, brown water, and to protect the pipes, iron is removed during treatment.
It is therefore iron deficient, and it is even probably the only element it truly lacks.

Fish don’t care.
But plants really need it.

👉 The solution I use is a liquid chelated iron fertilizer (often sold as "anti-chlorosis"), which I apply following a very precise protocol:

A little bit… from time to time!

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Trying too hard... often causes harm

Trying too hard often wastes time,
we set the bar too high,
and we often end up doing more harm than good.

Trying to change the "parameters" of water does not only bring good surprises.
And we ignore the number of things more subtle that we disrupt by trying to correct a single isolated parameter.

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My choice: make do with tap water

As for me, I have decided this:

👉 I make do with the water that flows from my tap.
👉 And I only create aquatic ecosystems that naturally thrive there.

This means that I adapt the plants and animals to the water I have, and I forbid myself the others.

The choice is wide enough, immense, infinite, so that I do not regret the species I decide not to harm.

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And rainwater?

Sometimes, I also use a bit of rainwater collected in the garden.
But it is not necessarily healthier than tap water.

I believe there are other aspects on which the time we devote brings more well-being to fish.

Let's rather fight to change the practices that contaminate our tap water.
But, on a daily basis, "making do" remains the wisest attitude.

 

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A happy fish tolerates water better than one might think

A happy fish, intelligently fed, as little stressed as possible,
becomes much more tolerant to physico-chemical parameters than one might think reading the literature.

Outside of extreme cases, a fish that becomes hypersensitive to common water parameters is often already weakened by other causes:

- transport

- stress

- inappropriate feeding

- excessive lighting

- solitude

- incessant noises

- lack of plants or hiding places

- etc.

👉 Certain aspects of captivity make one fragile.

Let's start there.

It's much simpler.
And much fairer.

 

To learn more about plants and nitrates: The magical power of plants