Fluval Stratum Caused Cloudy Water – What Should You Do?

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There’s no denying that the Fluval stratum is among the most nutritious types of substrates you could get for your aquarium.

This type of substrate contains potassium, iron, phosphorus, and several other components that are essential to optimal plant growth.

But what happens when the cleaning process is more difficult than you would expect or when the Fluval stratum makes the water muddy? That’s exactly what we will discuss today.

Do You Have to Rinse Fluval Stratum?

No, you should not rinse your Fluval stratum before adding it to your tank. For starters, that’s not really necessary.

Fluval stratum consists of larger pellets which will clean themselves easily once in the tank. The filter will suck in all the dust or debris that may come with your Fluval stratum.

On the other hand, rinsing the pellets may actually destroy them and turn them into mush. Not to mention, Fluval stratum is generally prewashed before being added to its package.

The only circumstance that requires you to wash the Fluval stratum would be in the case of poor handling during transportation.

Rough handling may cause some pellets to break, and the resulting dust and particles may cloud the water.

Just remember that if you need to rinse your Fluval stratum before use, you should do it gently to avoid destroying the rest of the pellets.

How to Clean Fluval Stratum?

The cleaning process begins the moment you’re adding the substrate to your new tank. If you’ve rinsed it prior, your Fluval stratum won’t need much cleaning afterwards. If not, cleaning is necessary to eliminate any debris, dirt, or crushed pellets that may have escaped the rinsing process.

In this sense, consider the following steps:

  • Add water carefully – Fluval stratum is very sensitive to agitation. Pouring water forcefully into the tank will not only muddy the water instantly but break the pellets and destroy the substrate’s composure as well. Instead of using the hose directly, consider an indirect approach. In other words, place a plastic container on the tank’s bottom and use the hose to fill it up. The water will pour gently over the container’s edges, allowing you to prevent stirring the substrate too much.
  • Drain out the excess residue – The water will get cloudy to some degree, no matter how careful you are about it. The debris clouding the water generally comes from crushed or broken pellets. Allowing them to settle isn’t an option because they will get stirred again at a later date. Instead, you should use a siphon to remove the debris-filled water and clear the environment.
  • Have a good filtration system – Once the tank is filled, you will notice that the water is still cloudy. This is normal whenever using Fluval stratum, despite all your efforts to avoid the issue. However, there’s nothing you can do at this point. Instead, you should allow the filtration system to do the work for you. The filter will remove the floating particles, clearing the water fairly fast in the process.
  • Now comes the really intriguing question – should you vacuum your Fluval stratum? The answer is negative. As we’ve mentioned, Fluval stratum consists of fragile pellets that are prone to destruction when agitated. A filtration system will simply act as a violent stirring mechanism, breaking all the pellets and creating more problems than you need.

Unless you actually need an extremely murky water, at which point vacuuming your Fluval stratum is a great idea.

How Long Does Fluval Stratum Take to Clear Up?

With a good filtration system in place and after performing a thorough cleaning, your Fluval stratum should settle completely within 24 hours.

This generally depends on the effectiveness of your filtration system and how much Fluval stratum you have. Sometimes it may take double that for the water to clear up.

How do You Get Rid of Cloudy Substrate Water?

Generally speaking, your best option is patience. If your water is still cloudy after 24 hours, give it some more time, and it will eventually settle.

If the tank water still doesn’t clear after 48 hours, consider performing several water changes to speed up the process.

In this sense, consider the following:

  • One water change per day – You want to perform one 10% water change per day until you get the desired result. You will probably only need 1-2 water changes for the situation to improve. Changing too much of the water at once or performing too many water changes within a day can change the water’s chemistry and parameters. Remember – patience.
  • Be gentle about it – I will reiterate it here – Fluval stratum is fragile. You last want to stir the substrate even worse during the water change. This will only exacerbate the problem instead of fixing it. Perform every water change with the utmost care to prevent an even cloudier water.
  • Long-term maintenance – Vacuuming your Fluval stratum is out of the question since this will break down the pellets and make the problem even worse. Instead, you should clean your Fluval stratum in a large fine strainer. This will prevent the breakdown of particles and preserve the substrate in its original shape.

Generally speaking, your tank’s cloudy water will clear up by itself over time. So long as you have a good filtration system, you shouldn’t worry about cloudy water too much.

Is Fluval Stratum Dirty Water Safe for Fish?

Cloudy Fluval stratum waters won’t kill your fish, but you should wait until the water clears up before adding the tank inhabitants.

The murky waters will cause your fish to experience some discomfort, and you don’t want to stress them out.

When it comes to avoiding substrate-related murky water in the long run, consider the following:

  • Avoid aggressive water changes – You don’t want to disturb your Fluval stratum too often. For this reason, you may need to perform more frequent water changes (1-2 times per week) for 10-15% of the total water volume. This is preferable to one 25% water change weekly since the latter can disturb the substrate in the process.
  • Avoid substrate diggersAfrican cichlids are out of the question and so are catfishes and other substrate digging species. Fluval stratum is soft and aerated anyway, so it’s of no use for bottom-dwellers.
  • No vacuumingVacuuming is forbidden for obvious reasons.

Plus, you should replace your Fluval stratum every 2-3 years at most. That’s because it will lose its nutritional characteristics, rendering it useless for your plants.


Fluval stratum is a highly popular substrate choice, given its nutritional content, esthetic value, and ease of use.

It does come with its minuses, such as increased costs, poor anchoring characteristics for newly-added plants, and extreme fragility.

Other than that, it delivers a handful of benefits, such as:

  • PH neutral
  • Doesn’t compact around the plants’ roots
  • Provides plenty of vital micronutrients for the plants to thrive
  • The best option for baby shrimp during their infant and juvenile phases
Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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