It’s pretty easy to get caught up in the moment when you’re setting up a new aquarium. First, you’ll seek out the perfect mix of fish species. Then you’ll size up your tank, and work out the logistics of keeping it clean and warm. From there you’ll probably start thinking about decorations and gravel. But what about the water? That always seems to be at the back of our mind when we set up a new tank. Which is strange because once you’re up and running you will spend some serious time making sure the water in your tank is good to go. So before you panic and frantically search google for how to make tap water safe for fish… read the guide below to get the facts on creating the best water for your tank.
Can you just use tap water straight from the faucet?
You can, but before you do make sure it’s safe for fish. If you live in the city there’s a good chance that it is treated with chemicals like chlorine and fluoride. And while those are added to make water safer and better for human consumption; they may be toxic to your new fish. And, if you your water is supplied by a well there are a bunch of other potentially harmful things (to fish) in that tap water.
So before you fill the tank or even start thinking about buying a fish… take a good hard look at the water you plan to use. There’s nothing worse than the feeling of getting everything set up only to kill off your new pets because you didn’t do your homework.
How to Test and Treat Tap Water for a Fish Tank
Tap water varies greatly from one location to another. One town may have a lot of chlorine, while the next’s water is far to acidic to support aquatic life. The main things you’ll want to check are pH, Carbonate Hardness (kH), and general hardness (gH). You will probably want to check Nitrites, Nitrates, and Ammonia as well. Although those last ones are more of a set to monitor after fish are living… and producing waste; in the water.
The kit above will cover the spectrum of things you’ll want to test for in that tap water. You can also ask your local fish shop about the water in your area, but even then there may be some serious variances within your city. That option might be best for locations where tap water is a definite no, for aquarium use. In most cases you’ll want to test the water you’re going to use directly from the source.
pH
We have a great overview of pH in a guide we recently created about alkalinity in drinking water. However, for the purpose of testing the pH of aquarium water… you’re typically looking for a number between 6.6 and 7.8. Which is right around neutral (7.0) as you learned in science class. Now, there are some exceptions to pH in for fish, but those are very species specific. So before you add a new fish to the mix just take a look at that species’ ideal pH.
kH
Calcium Carbonate (kH) is the white stuff that builds up on showerheads and other things in your home. Some fish are hard water fish and others prefer softer water, but kH also stabilizes your pH levels and provides important minerals to your pets. Manipulating kH is a topic better left for other discussions, but most test kits will tell you if it’s at a good level. 4-8 kH is a good zone for most freshwater fish.
gH
General hardness (gH) test for a number of minerals, other than kH. Minerals like Magnesium and Calcium which help fish grow and thrive.
| Hardness | PPM | DH |
|---|---|---|
| Very Soft | 0-50 | 0-3 |
| Soft | 51-100 | 3-6 |
| Slightly Hard | 101-200 | 6-12 |
| Moderately Hard | 201-300 | 12-18 |
| Hard | 301-450 | 18-30 |
| Very Hard | > 450 | > 30 |
***4-12 gH is ideal for most freshwater fish, African Cichlid’s 12-20 gH
Heavy Metals
Heavy metals like Iron and Copper do have some benefits in a fishtank. But, too much can be very hazardous. Other heavy metals like Lead, Mercury, and Arsenic are definitely something you do not want for your fish or your family. We highly recommend using a reverse osmosis system to remove these hazards, but we’ll cover that in greater detail below. If you want to test for heavy metals you’ll need a test kit or two.
There are fish tank specific test kits out there, but we think the above example from Test Assured trumps them all for a number of reasons. The main one is that we’re talking about tap water here. That’s not just for the fishtank… it’s the water your family uses to drink, bathe, and cook with. This is a great opportunity to “kill two birds with one stone.” You make sure your fish will be off to a healthy start, and you get a solid idea of what your family consumes on a daily basis. From there you can take action. More on that below…
How to Make Tap Water Safe for Fish After Testing
Once you have an idea of what’s in your tap water you’ll be able to make a plan to get it just right. There are a wide range of products to prepare and maintain the water in your aquarium. And, with the growth of online shopping you have so many more options to do so with chemicals or naturally.
Step 1 De-Chlorinate
One of the chemicals that will harm a fish most is chlorine. Always let tap water sit for 24 hours so the chlorine has a chance to evaporate. Or you can treat the water with another chemical if you’re not able to wait. API’s tap water conditioner is a great choice. You’ll actually need to use it if the water has difficult to evaporate chloramines…
Consider adding an aerator to your water while you wait for the chlorine to evaporate. Doing so will help speed up the process.
Step 2 Remove Heavy Metals (if present)
If you need to remove heavy metals you can always use a fish-specific product like Two Little Fishes MetaSorb But, we think that’s an approach that should be taken down the road in the event that you discover heavy metals in a tank with fish already present. But, for those who discover heavy metals in the testing process we laid out above… a Reverse Osmosis (RO) purifier is the best route.
You can spend a ton of money setting up a whole house RO system, but point of use models like the one above can be had for a very, very reasonable price. So low that you can probably afford to set up multiple filters throughout your home. They’ll remove a wide range of contaminants from your drinking/fish tank water. And some even come with remineralizers that correct things like pH, since reverse osmosis strips so many things away while it filters your water.
Reverse Osmosis one of the best tools to make tap water safe for fish without chemicals.
Step 3 Condition
After you remove the chlorine you’ll want to condition the water in preparation for your new pets. Even if you’ve removed the chlorine, there may be other things lurking in that water ready to harm your fish. And if you’ve used a RO water filtration system you basically have a clean slate to build upon. Either way conditioning is a great idea. In fact we would go as far to say that it’s a necessity.
This is also a good time to move the water to your fish tank if you haven’t already. It’s also a good idea to fire up your filtration system to get things moving.
Conditioning may require the use of chemicals, and that makes some people uncomfortable. So we’ll look at some natural options after we cover the more common means of conditioning.
The Chemical Route
One of the most highly regarded conditioners is API’s stress coat, pictured below. It’s a solid replacement for the Tap Water conditioner we mentioned above if you also want to chemically remove heavy metals. But its primary use is to create a synthetic coating that replicates a fish’s natural protective coating. Which is often reduced or lost in transit. There are others you’ll want like Quick Start, but rather than that we’ll cover the Perfect Start Kit Below.
Perfect Start (pictured below) contains some of API’s most popular products like Quick Start, Stress Zyme, and Stress Coat. All are pre measured and marked with an interval that corresponds to when you should add each packed to the tank. On day one you add the first packet (contains STRESS COAT, QUICK START & API AQUARIUM SALT). On day 14 you’ll add packet two (contains STRESS COAT, QUICK START & AMMO-LOCK). Finally, on day 28 you add the third and final packet (contains STRESS COAT, QUICK START & STRESS ZYME).
Chemical Free Options
If you opt out of chemicals you’ll definitely want to use a reverse osmosis system. But, remember RO water is gH and kH deficient.. so plan accordingly. Some people consider distilled water are not only extremely expensive (unless you make your own), they’re much more difficult to condition. Plus they’re also devoid of any minerals. If you’re going to buy water spring water may be a good option, but it will also be expensive and need some conditioning. Other bottled water is viable as well, just make sure to test it before you condition.
You’ll also want to avoid using lake, river, or pond water. Those have a lot of other complexities and contaminants you’ll have to test for and correct. Aside from buying preconditioned water from your local fish shop… conditioning purified tap water naturally is the way to go.
To condition purified water naturally consider using crushed corals, dolomite filters, or decorative limestone in your aquarium. Any of those will raise pH levels. As do aquatic plants.
If you need to lower pH levels naturally by adding some natural decorative driftwood or by introducing CO2 into your aquarium. The latter will also help with those aquatic plants we mentioned above.
Baking soda will raise kH naturally and if you want to add other minerals back into your RO water. If you want to raise gH naturally… try the crushed coral or limestone we mentioned above.
