Skip to Content

Why Flourite Substrate Causes Cloudy Water!

Fish keeping is one of the fastest-growing hobbies in North America right now and although keeping fish has been seeing solid growth each year for decades, over the last two to three years the number of people getting into fish keeping has been at an all-time high.

With there being so many people new to the hobby, we have seen a number of questions about the common problems people have when keeping fish with many people asking about Seachem Flourite causing cloudy water.

Seachem Flourite is one of the more cloudy substrates by far and although it is an excellent substrate option, the majority of people should rinse their Seachem Flourite substrate prior to putting it into their tank to reduce the cloudy effect.

Even then though, you will often have to leave the substrate to sit for between one day and one week as it can be a pain to settle if you have bottom-dwelling fish or a high water flow tank.

We are fully aware of the fact that some of the competing substrate options on the market not having this requirement prior to use but Seachem Flourite makes up for the minor inconvenience of having to rinse it prior to use in other ways.

This is why Seachem Flourite is such a popular substrate option within the hobby and it has an excellent reputation within the community as well as a relatively low price tag considering how good the product performs in the majority of aquarium setups.

How Long Does It Take Flourite To Settle?

It can take Seachem Flourite substrate as long as a week to settle in your tank and for the cloudy water to clear.

In most cases though, your aquarium water should clear within 24 hours after adding fresh Seachem Flourite substrate to your tank, especially if you have a low water flow tank without any bottom dwelling fish in it.

As we mentioned above, you can reduce the amount of particles that your Seachem Flourite can kick up when being added to your tank by rinsing it prior to adding it to your tank.

This will usually keep your settling time for your substrate to less than one day and allow you to view your fish sooner but there can be some issues with rinsing your substrate that can cause problems too but we will cover those later in the article.

We have seen some people on social media recommend that you mix other substrates in with your Seachem Flourite in an attempt to prevent it from clouding your aquarium water but we don’t recommend this.

Not only does it do little to nothing to reduce the issues with your tank water clouding up but adding other substrate, especially random sand that you find at a beach can present a risk for parasites, fungus, and bacteria to get into your tank and potentially cause serious problems.

Just stick to your Seachem Flourite directly from your bag and don’t waste your time and effort by taking the risk of adding other types of substrate to your Seachem Flourite.

Why Flourite Substrate Causes Cloudy Water!

Seachem Flourite substrate can cause a surprisingly large amount of cloud in your aquarium water due to the number of loose particles in the substrate essentially acting as free radicals in your tank prior to settling.

This can drastically reduce the visibility of your tank but these free-floating particles of substrate will eventually settle and let your water clear up in time.

Some types of Seachem Flourite substrate have more of these particles in them with their sand based substrate products usually being the more difficult to deal with then it comes to your tank water going cloudy for a couple of days after new substrate is added.

The clay variants of Seachem Flourite substrate tend not to be as bad as their sand options when it comes to clouding your tank water up so if you are able to use one of their clay options over the sand options then that can be a quick and easy win.

Even if you do switch over to the clay Seachem Flourite, there will still be come clouding though but it will usually clear within a day or two opposed a three to seven days if you are using their sand substrate.

When it comes to color matching, you can usually find a clay variant to match the color of the sand variants of the substrate too so there really is no need to have a drastic change to the look of your aquarium tank.

How Do I Fix Cloudy Substrate Water?

The easiest way to remove the cloud in your aquarium water caused by Seachem Flourite is to simply wait and let the substrate settle naturally.

Unfortunately, this can take as long as a week in some cases but the cloudy should start to fade within a day and be gone within two to three days for the majority of people.

You can usually reduce the amount of cloud caused by your new Seachem Flourite as well as the time required for the cloud to fade by rinsing your Seachem Flourite prior to adding it to your aquarium.

Cold water will get the job done and simply rinse the Seachem Flourite substrate for a couple of minutes and then try to get rid of as much of the loose substrate particles as possible by pouring the water out.

If needed, you can do this multiple times but you really do start to see diminishing returns on the effectiveness of this method after your second rinse so two rinses is usually the maximum we would recommend.

Once you have rinsed your substrate, try not to let it fully dry again as the oxidization of the Seachem Flourite can cause more particles to be created so try to add your substrate to your aquarium as soon as possible after rinsing it to keep the Seachem Flourite wet and as particle-free as possible to prevent or reduce clouding.


That brings our article going over why Flourite substrate can cause cloudy water as well as how you are able to reduce the cloudiness to an end. Most people tend to just let their substrate naturally settle in their tank by waiting rather than using the rinsing method but if you do have bottom dwelling fish in your tank that will kick up the substrate then we would recommend that you take the time to rinse your Seachem Flourite prior to putting it in your aquarium to prevent any future clouding.