Best Reef Cement: Up Your Reef Tank Game

Best Reef Cement: Up Your Reef Tank Game

Reef tanks and cement don’t go together. That’s a pretty controversial way of starting this, isn’t it?

Let me rephrase that. You can’t use all types of cement inside your reef tank. All of them aren’t safe for the aquatic ecosystem. And some of you might have learned that the hard way.

Only cement can hold rocks underwater strongly enough. And if you’re considering cement, then you probably had failed attempts with other adhesives.

Don’t fret.

We went on to do a bit of research in search of the best reef cement. And there isn’t a simple answer to this trick. We made sure all the cement got a proper shout. Our comparative analyses should help in that case.

So let’s dive into the central part. 

Types of Reef Cement

Before getting too far into the comparison, you should know that there are different types of cement. That’s right, don’t get straight to using just any cement for your reef tank.

After categorizing for a little bit, I think we can sort these into reef cement, PVC cement, and hydraulic cement. And we’ll be talking about the top picks from each category here.

Reef Cement vs. PVC Cement vs. Hydraulic Cement

So which one is the right choice? Are the cement dedicated for use in reef tanks the right ones to go for?

Do you know what I think? It’s just another marketing ploy using pretty packaging and a pretty price point. 

I think hydraulic cement works as well as reef-specific cement, but we’re still going to show you the comparison. 

Reef CementPVC CementHydraulic Cement
Best forGood for coral fragging and attaching ceramic rocks. For attaching rocks Bodybuilding Motivation 2019 HD – KEEP PUSHING alphabolin vial bodybuilding and fitness female motivation 2013 and preparing surfaces.Best for attaching ceramic rocks and preparing surfaces. 
When Not to UseDon’t use these for preparing tank surfaces.Not recommended for fragging coral plugs. Not so good for coral fragging. 

Cement vs. Other Adhesives

As you probably already know, cement isn’t the only adhesive used for reef tanks.

The most common type of adhesives includes reef glues and epoxy. While we don’t vouch for all types of glues, cement has a wider use case.

You can only use reef glues for coral fragging. They’re strong enough to stick plugs with coral frags onto different rocks inside the tank.

But you can’t use glue to stick the larger rocks with each other. So this is where the cement comes into play. 

Don’t get us wrong. We’re not vouching for cement. There are just a couple of things that the reef glues do better. While glues have a smoother texture, cement will have a slightly crumbly texture. 

This makes glues look a bit superior to cement. 

But cement has its forte too. So, let’s get into the comparison without any further ado. 

Top 6 Best Reef Cement 

Firstly, we’ll take a look at the cement that’s only used for reef tanks. We’ll also tell you how they fair against the other cement along the way. 

This was a quick comparison. We’ll show you a bit of a visual representation now. Check out the graph below- 

Disclaimer: The lower the curing and the setting time, the higher their points here.

NYOS Reef Cement: Best for Coral Fragging

Keeping all the criticism aside, the marketing team did try their best to make this one stand out.

The segment of reef cement isn’t vast. And most people would rather use conventional ways to frag corals too.

To those guys, I’d say give this one a try. This is the only cement that we used with coral frags that worked out well. 

We’re not going to talk about the container. You might as well confuse it with a box of ice cream. That’s probably what you’re paying for.

I know this isn’t the most cost-efficient way to get things done. But the others couldn’t live up to the fragging game that this one offers.

Finding a non-toxic cement that doesn’t kill your fish is tough. We tested this one out with different fish and corals. Well, I don’t know if they were affected since they didn’t show any changes.

Now, mixing this is probably the toughest job when you’re comparing it with other adhesives. Glues and epoxies are just plug-and-play options.

But when you’re comparing it with other cement, this one comes out on top. It’s the pricing and quantity where this one drastically disappoints.

I don’t think anyone would pick this one over a regular hydraulic cement if attaching rocks was the only task.

Although it sets fast, you get decent wiggle room. So you can still reposition the coral frags once you’re done attaching them. 

If you actually want a bit more reef cement, you have to move on to the next product from Aquaforest. But NYOS does have a better overall reputation.

Things That Need Improvement:

  • You don’t get a ton of cement here. This isn’t the practical solution if you want to buy in bulk. Try out the fifth cement on the list if you want a bulk solution. 
  • This might seem a bit overpriced. If you just want to attach ceramic rocks with cement, try out the Quikrete cement. We discussed it further down

Aquaforest StoneFix Reef Cement: Best Budget Reef Cement

Up next, we have something that comes close to the NYOS cement. I think they just smoked the same thing the makers of NYOS did.

It’s another one of that pretty packaged cement with a steep price tag. This does cost more than the NYOS one. But you also get three times the quantity. So there’s that.

The only reason why this one ended up in second place is the curing time. It sets faster than the previous one. But it takes up almost twice the number of hours when it comes to curing.

You also don’t get a ton of wiggle room once it sets.

This pack includes most of the reef cement ingredients like the other five. We’re no chemists, but this contains what seems like limestone, clay, and gypsum. These make the cement set quicker than conventional cement.

I think this has a better chance of being used for attaching ceramic rocks.

We tried to attach frags with this. The results weren’t too pretty. But using it with ceramic rocks did the job. We tried to attach the rocks underwater. 

Well, you can see the cement particles floating all over the place when you’re working with it underwater. This is something we didn’t notice with the NYOS one.

Since the cement isn’t toxic, those particles shouldn’t be alarming. But it’s best to attach the rocks to a fishless tank if you can. 

Things That Need Improvement:

  • This takes too long to cure. If that’s something that bothers you, try out a faster curing cement
  • The wiggle room could have improved. You don’t get too much time to work after application. If this seems concerning, try out our previous recommendation. 

Two Little Fishies STIX Cement: Best New Entrant

The quantities keep increasing as we go further down the list. You get a lot more cement if you pick this one from Two Little Fishies.  

It’s the new kid on the block, and it’s perfectly dedicated to attaching rocks.

We tried the other tests like on the other cement. And, well, this one drastically failed when it comes to attaching coral frags.

I know it wasn’t made specifically for this purpose, but it’s still the same ingredients, right? Well, you get more quantity. So you can do quite a bit of aquascaping with this.

Where this stands out is that it comes with liquid polymer. So that’s a few extra materials that the others don’t provide. 

They also provide a spatula. But the quality isn’t really amazing. You can probably use any other spatula for cement mixing. That would probably fare well anyway.

In terms of mixing, well, the mixing process gets a bit more complicated in this case. You have to mix a few more things than the rest. So this gets a few fewer marks than the others in the practicality aspect.

What we don’t appreciate is how fast it sets. If you compare this to the NYOS in the first spot, this one seems impossible to work with. Just keep that in mind if you’ve already made up your mind on picking this.

Things That Need Improvement:

  • Too little wiggle room. This might seem hard to work with. So pick a cement that provides better wiggle room.
  • This does not have many use-cases at all. If your only aim is to join ceramic rocks, this is decent. But if you want coral fragging performance, try out either of the first two.

Quikrete Hydraulic Cement: Best Hydraulic Option

If you still want something bigger than the previous three, well, this is it.

You get a whopping 10 lbs here. And they also give this much cement for almost the same price as the NYOS one. 

This is a typical hydraulic cement that works underwater. Well, we’ve already proven that the entire thing about reef cement is kind of a hoax. This one has all the reef cement ingredients too.

So hydraulic cement is basically the same thing.

We’ve tried this out with coral frags and attaching rocks. Well, this didn’t work well with the frags at all. We tried to stick some plugs onto the corals. And this isn’t designed to work like that.

Although the cement set within a few minutes, the corals weren’t sticking. So we went through to our second test.

And this time, the Quikrete worked. We were able to attach heavy rocks with the cement. Now, it does take the whole night to cure, but the strength is pretty decent.

We even tried to pull the heavier rock from the joint end. And it didn’t break. So that’s a plus point. Even the Aquaforest StoneFix didn’t show this much binding strength.

Things That Need Improvement:

  • I’d say this takes too long to cure. If you want to work on a project fast, try out the NYOS reef cement. We’ve already discussed this earlier. 
  • You don’t get good wiggle room. If you want to make adjustments after application, you can try out either of the two top choices.

Sakrete Leak Stopper Hydraulic Cement: Your Bulk Cement Option

Here’s something you might want to use in bulk. The big 50 lbs tub won’t run out anytime soon. This is something you can’t do with the other cement on the list. 

You could probably use the tub for ten reef tanks, and you’d still be left with a lot of cement.

There’s also the smaller option. But I don’t think it’s as cost-efficient as this is. 

The cement was originally developed as a leak-stopping hydraulic cement. Now it’s making its name as a decent reef cement. Not bad for “regular” cement, right?

What separates this from the others is that it dries gray. We even tried to make our tank surface with this one. And the cement seemed to have worked decently. This isn’t a feat that the others did well.

Things That Need Improvement:

  • This might seem a bit too heavy for you. If you want smaller containers, you can try out the smaller version
  • Although it comes with a lot of cement, it takes a bit too long to cure. 

Oatey 30246 PVC Cement: Your PVC Cement Option

Lastly, we have this combo from Oatey. Upon research, this is the only PVC cement that seemed to work with fragging. Well, kind of.

If you attach frags with plugs outside the tank, this seems to work. But when you work with this underwater, this isn’t even close to the others.

You do get a primer with this. And it’s purple. But the primer would be pretty useless for your reef projects. But the cement works well. You could leave the primer for other house projects.

As for attaching rocks, this is decent. I’d say this ranks third when it comes to the bonding strength of attaching rocks. You still have to let it cure overnight.

It’s not the best in terms of curing time, but you have to realize that it wasn’t made to work with reef tanks. 

What we did not like is that you don’t get a whole lot of cement. It’s just 4 ounces. I mean, it’s cheaper than the rest, but it’s still kind of disappointing. 

Things That Need Improvement:

  • The quantity is way too little. You probably have to opt for the bundles in this case. 
  • You get average wiggle room. I mean, you could work with it after application, but not for long. If this is a concern, try out the NYOS cement up top. 

How to Use Reef Cement?

You probably think that reef cement could only be used for attaching coral fragments. Well, that’s not true.

I think cement has a couple of other use-cases when you’re using them in your reef tanks. So let’s talk about those-

For Coral Fragging

I know a lot of you won’t be using cement for fragging. But it’s still an option. In my opinion, you need a few extra steps to get this going. Mixing the cement with water and preparing the cement might seem like a bummer.

But the result isn’t that bad. It’s comparable to other adhesives. But you might think that the cement attaching the coral fragments might seem a bit crumbly.

That’s just the texture of the cement after it dries. There’s nothing you can do about it, really. 

For Attaching Rocks

I know you’ve seen people attach giant white rocks inside their reef tanks. Normal glues aren’t really strong enough to hold the weight of the rocks. They’ll give in eventually.

That’s where cement comes in to save the day. Once cured, cement can hold heavy rocks together underwater.

We tested them out to see whether they could live up to their names. Most of them passed the test. 

Preparing the Surface

Lastly, you can use reef cement to prepare the surface of your tank. I know this isn’t as popular as the other two methods. But this works. 

You can use cement-like these on the surface when you’ve just started to set up your reef tank. No matter which substrate you choose, cement will help you while attaching them.

You can prepare the entire surface of your reef tank using hydraulic cement. This also allows you to test the strength of the cement.

Reef Cement: The Cons

After months of research and holding talks with experts, we agreed on something. These cements aren’t the best at everything they do. 

And I think most of the complaints arise from the likes of us. I mean, would you prefer reef cement over glues? I don’t think so.

This is probably because glues are straightforward. You don’t need to mix anything with water when you’re working with glues. 

The same goes for the epoxy putty. You just have to roll them into balls and put them in between gaps. Maybe making reef cement balls isn’t such a bad idea, right?

Well, the structure of cement is crumbly even after mixing it with water. While this doesn’t hold a lot of demerits, most of you would avoid it. 

Even if you want to skip cement for attaching rocks, you can’t. Cement is the only adhesive here that has a higher bonding strength. Some of them can hold weight better than others. 

And as for surface preparation, cement is probably the only way to go. So you can’t avoid it in the long run. 

Frequently Asked Questions

Can you put cement in your reef tank?

Cement works decently inside reef tanks. If you get a certain version of hydraulic type cement, they shouldn’t interfere with the ecosystem. So, yes, you can easily put cement in your reef tank.

Is Cement Reef safe?

Before jumping to conclusions, you’ll probably need reassurance.

This one’s a little tricky to answer. All cement isn’t reef safe. There’s a specific type of cement that can be used with reef tanks. And those are the ones we looked at today.  

How long until PVC Cement Reef safe?

PVC cement will become reef safe in around 24 hours. If you’re not in a rush, let it cure for around two days. But you can get to work after twenty-four hours, though.


That’s it from us. We’ve shown you the products that we thought were good value for the money.

I know that some of them came out on top when we headed into the comparison. But they’re still top picks. And you can get different use-cases from them too.

If you’re confident that you’ll be using reef cement cement-like, I think you can pick the best reef cement here.

You can come up with your own comparative bases if you want. While we have crowned a winner, you always have the right to choose. So choose wisely. Good luck! 

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