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Tap Water - What do you need to know?

21st Nov 2019

Topping up your pond with tap water is something you will have to do, well that is unless you have an abundance of water butts around your garden. Why are we talking about it then? Well tap water contains many things which are perfectly safe for us to drink, however fish are more sensitive. Now yes, I know you will have a friend who has never used a treatment and their fish may be absolutely fine. It is true that fish can build up a tolerance to poor water quality, however that’s not the right way to look at cutting corners in my eyes. Ultimately you might not notice it, but your fish will suffer from the main antagonist in tap water which is Chlorine.

Chloramine and Chlorine will be used by your water board to allow them to deliver you safe drinking water, it will arrive in your tap at around 1.5-2.0 mg/l. For pond inhabitants this is unsafe, at 0.05 mg/l chlorine can be toxic. Chlorine will over time naturally be removed from water, however it is not highly reliable. For 1mg/l of chlorine it needs 20 hours of time to pass for removal.

Top Dangers:

When a pond's PH levels go down Chlorine becomes more toxic.

In a high concentrate it can actually kill your fish.

Chlorine kills good bacteria (beneficial for the health of your pond and filtration) and can allow some harmful chemicals such as Phenols to combine with the Chlorine.

Chlorine over time damages the gill structure of your fish, check out why this is important in my Fish Anatomy Blog!

A fish has a protective slime covering their bodies, chlorine removes this.

Can I notice a Problem?

As mentioned before Chlorine in certain levels isn’t noticeable, if you have a high concentration of it though you may notice sores or general signs of irritation from your fish. You may notice your fish jumping and trying to leave your pond, this is very similar if you have high levels of ammonia, so remember to do regular water checks.

How do I remove it?

The easiest way I’d say is with the inline Dechlorinators, you have to have a rough idea of water that you’re changing and keep a record, but it is 100% reliable in removing Chlorine and heavy metals. These contain Carbon filters where the water from your tap runs through. The Oase one pictured is good for 200,000 litres, they are very simple to fit as well!

More commonly used however are liquid style treatments as the initial expense is much cheaper. They are also easy to use and we stock a Whole Range, the best value being our own PondKraft Treatment.

So the next time you reach for your hosepipe have a think about the above.