The Best Substrate for a Red Eared Slider

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Whether you are a new or an experienced Red Eared Slider keeper, what kind of substrate to use in your tank is always a hot topic and everyone has got an opinion. Including yours truly.

There are 4 types of substrates that hobbyists use in their Red Eared Slider tanks and I am going to talk about all of them.

The main points I am going to go over will include aesthetics, sanitation, enrichment, and any impaction risks.

Ready? Let’s go!

Bare Bottom

“Bare Bottom” is the simple way of saying having no substrate at all. It is by far the safest and cleanest option out of all four. Not using any substrate is a great option for Red Eared Sliders because they are messsssyyyyy. It means you can easily and quickly scoop out any waste which can negatively affect the water parameters. The downside is that it is not very appealing visually and in my opinion, lacks the opportunity for enrichment.

Pros:

  • Easy to clean
  • No impaction risk

Cons:

  • Not visually appealing
  • Lacks enrichment

Gravel/Pebbles

I could list the pros and cons of using gravel or pebbles in your tank but I really do not want to promote the use of these options in any capacity.

Turtles are opportunistic eaters and will try to eat pretty much everything. Because of this, gravel and pebbles have caused NUMEROUS documented deaths and are not worth the risk considering there are much better and easier alternatives.

So please, don’t use gravel or pebbles in your turtle tank. I don’t recommend them at all. Some people will say it’s perfectly fine and they have never had any problems, but to everyone else; please don’t use gravel or pebbles or anything similiar in size where the turtle can accidentally swallow and get choked or impacted.

Pool Filter Sand

I specifically stated “Pool Filter Sand” and not just “Sand,” because I along with many other Red Eared Slider keepers will only recommend Pool Filter Sand if you choose this type of substrate. If you go with this option, make sure you get non-aragonite (aragonite is used in saltwater tanks and can really mess up your water levels if used in a freshwater tank) pool filter sand and make sure it is a good quality around 20-grade silica. Want to know where you can find some? Keep reading!

Pros:

  • Visually appealing
  • Easy to clean
  • Low impaction risk
  • Offers enrichment

I like pool filter sand because it is very natural looking and not too hard to clean. It obviously requires more work to clean than a bare bottom tank but definitely not as hard as river rock or creek rock.

It also has a very low impaction risk which is very important when dealing with Red Eared Sliders.

Plus it also offers enrichment. Red Eared Turtles are what we call “soft-shelled” and these types of turtles love to bury themselves underneath the sand. Which is another reason why I don’t like using gravel or pebbles as this can really damage their shell if they try to bury themselves.

Cons:

  • Can be hard on filters
  • Has a slight impaction risk
  • A breeding ground for certain anaerobic bacteria

One of the biggest complaints with using any type of sand is that it can be hard on your filter and can clog the impeller. If this is the case, you should move your filter intake up a couple of inches away from the sand bed.

Secondly, I still put that pool filter sand has a slight impaction risk because I wanted to make this point: this should go without saying but if you find that your RES or any reptile for that matter is just continuously eating their substrate, there is something wrong! It could be a calcium deficiency or something very serious and you should remove the substrate and take them to an exotic vet.

Lastly, what are anaerobic bacteria? It is bacteria that live and grow without oxygen and can be found at the bottom of deep sand or gravel beds (over 2 inches). There is a mixed debate with hobbyists about whether stirring or vacuuming your sand can help prevent the growth of anaerobic bacteria. My recommendation? Don’t use more than two inches of sand, have an appropriate size filter for your tank and turtle, and keep your tank cleaned regularly.

River/Creek Rock

Arnon loves river rock. It looks awesome and she likes to use her claws and turn them over to look for ghost shrimp. The downside is that if you use only river rock, it can trap debris and waste underneath of them making it harder to keep the tank clean and the water parameters where they are supposed to be.

Pros:

  • Visually appealing
  • Offers enrichment (turtles like to dig and turn over stones)

Cons:

  • Hard to clean

My recommendations

New Red Eared Slider Keepers:

First and foremost, if you are new to the Red Eared Slider world, you should definitely stick to a bare bottom tank for a while until you become more familiar with your turtle. I say this because every turtle is different and it is up to you as their keeper to monitor their behavior and ensure that all of their needs are being met. This is so much more important than what type of substrate looks best in your tank. So bottom line, if you are still new to keeping a Red Eared Slider, wait a while before adding any substrate and use this time to concentrate on their care and behavior.

Experienced Red Eared Slider Keepers:

Now, what I use and recommend for the more experienced keeper is pool filter sand with different size river rocks. As you all know, I am usually an advocate for not using any substrate that has an impaction risk. The reason I chose to use this type of setup is because I have monitored our Red Eared Slider for almost a year on both a bare bottom tank and river rocks and I have witnessed Arnon try to eat non-food items and then spit them right back out. I have also spent countless hours doing my own research about Red Eared Slider care; tank size, lighting and heating requirements, food schedules and water parameters just to name a few. Therefore, I am confident that it won’t be a problem for her.

Where can I find the right Pool Filter Sand?

The best pool filter sand that I recommend is FairmountSantrol AquaQuartz-50 Pool Filter 20-Grade Silica Sand* and can be found on Amazon. It comes in a 50-pound bag in white so it looks really natural and it’s extremely affordable for such a large bag. Bonus: It’s extremely easy to clean compared to other aquarium sands. I only had to wash it once before putting it in Arnon’s tank!

Also, it hasn’t seemed to affect our filter much. We use the Fluval FX6* and I made sure to raise the filter input so the bottom of the input was 3-4 inches away from the sand. Another added bonus is that this sand* doesn’t kick up easy so when Arnon is speeding around her tank, it stays on the bottom.

But if you are still unsure, you should always go with the safest option, which in this case would be a bare bottom tank.

What if I want a planted tank?

You can still have a planted tank even if you don’t use gravel or pebbles!

First, you should make sure the plants that you are planning on using are safe for your Red Eared Slider.

The top two plants that are the most recommended for Red Eared Slider tanks are hornwort and java fern because they are hardy plants and do not need to be rooted in a substrate in order to grow.

Other safe plants you can use are water lilies, elodia, duckweed, java moss, anacharis, and arrowhead just to name a few.

What kind of substrate do you all use in your Red Eared Sliders tank? Let me know in the comments below!

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16 thoughts on “The Best Substrate for a Red Eared Slider

  1. hi! our red eared slider found us. we opened the front door one day and there she was. she is about 10 yrs old give or take based on her shell. we made the mistake of rocks the first week we had her and of course she pooped rocks for quite a while after. its been a bare bottom tank since then. thinking of trying the sand you mentioned above. do you ise a certain type of vacuum to clean it? and if so how often. right now shes in a 150 tank and my son does total water changes weekly or it starts to smell turtl-ish in his room. i feel like we should be able to go longer between water changes.

    1. Hi! I would recommend steering clear of sand if your red eared slider has eaten rocks in the past. Sand is definitely better than rocks/pebbles but it can still cause impaction. If you still decide to go with sand, you can use any type of gravel vacuum and hover over the top of the sand to clean the debris. I use Aqueon Siphon Vacuum with Priming Bulb Aquarium Gravel Cleaner and I try to clean her sand every time I do a water change. I recommend doing weekly 25% water changes. If you remove all of the water, it will start the water cycling over which will kill all of the beneficial bacteria. Water cycling can take a while to complete so I would recommend doing some research on that if you haven’t already and investing in API Freshwater Master Test Kit, it definitely helps to see where you are at in the water cycling stage. As far as the turtle smell, I totally understand! I would make sure you are using an external canister filter that is rated two to three times the size of your tank. So if you have a 150-gallon tank for a red eared slider, your filter should be rated for 300 gallons at least. Turtles are extremely dirty so that would definitely help with the smell. I hope this helps! Let me know if you have any more questions 🙂

  2. Hi, I have Bella, a female Red eared slider. She is now 9 years. She has never layed eggs. She has her own water tank and also a nesting area. Gets her vetrivit drops too. She eats tubifex cubes,taiyo turtle pellets and vegetable greens too. She is active but never laid eggs. Is it ok?

    1. Hi!

      Thanks for reaching out! That would definitely cause some concern for me. There are numerous reasons that could be the issue, I would strongly recommend taking her to an exotic vet to have her checked out. They will be able to go through everything with you and hopefully figure out the underlying reason.

      Thanks!

      Shelby with New Hope Herp

  3. I have a red eared slider named Sally(monella) and she likes to try to eat the silicone on the bottom on the tank and so I want to get substrate so she doesn’t eat it but I think she will also eat the substrate. I think if I did rocks, she would push it away to get to the silicone since she is quite smart and if I did sand she would just eat the sand. Do you have any subjections to what I should do

    1. Hi! First, that is an adorable name! And I agree, I would definitely be concerned about her potentially eating substrate if she’s already chewing on the silicone inside her tank. There are a couple of suggestions I would make: One, it could be a calcium deficiency. Assuming that she is an adult and has a proper size tank with a basking platform and full spectrum heat/lighting, she could be gearing up for her egg-laying season which is coming up soon. They need a lot of extra calcium before they lay their eggs. Zoo Med makes a good Turtle Bone supplement and you just put it in their water and the turtle eats it at its leisure. If that’s not the cause, she could simply be bored. Try putting some live ghost shrimp in her tank for extra enrichment and protein. Most local pet stores that sell fish have them and they’re fairly inexpensive. As always, please consult a licensed exotic vet if you are concerned at all. I hope this helps!

      Shelby with New Hope Herp

  4. Hi Shelby, thanks for this blog. My RES Zazzy has been trying to woo a pleco named Sucky for many years. Recently it’s turned violent and Zazzy stalks him. Poor Sucky has to hide all day while his wounds heal, so I just set up a new bachelor pad tank for Zazzy. He moves tomorrow. I am worried he will be lonely and I want to give him more in-tank enrichment – any suggestions? I already pet him (in tank) and occasionally I take him out and use a toothbrush on his shell. I have a bare bottom tank right now but am thinking, based on your blog, I should get some river rock. What other things can I add to the tank for enrichment?

    1. Hi!

      You are very welcome! River rock would be a good idea or sand if you think it would work with your setup and you’re confident your RES won’t try to eat it. I would also recommend adding several ghost shrimp to the tank. They are really inexpensive and you can find them at almost any pet store. They are a good protein source for red eared sliders and turtles love to chase and hunt them. You could also add a calcium supplement like a turtle bone.

      I hope this helps!

      Shelby with New Hope Herp

  5. Howdy! I have two RES one is about 18 and the other is 3 – both named Phil, both female, hah.

    I’ve been struggling with substrate now that I have them together in one tank – I use river pebbles but its just too much to keep up with cleaning. I love the idea of using sand but I am curious on how exactly you clean it? I Imagine it would get sucked up in a “substrate vacuum” with all the debris so I’m just curious to how it works 🙂

    1. Hi!

      Hah! That is too cute!

      I clean Arnon’s sand with a gravel vac – I just stick it in the sand and pull it up quickly and hover it over the sand bed a couple of inches. This will stir up the sand but suck up the debris into the gravel vac. I also just use a net to clean the big debris on top of the sand. But if you want a really easy cleaning option, I would recommend a bare bottom tank.

      I hope this helps!

      Shelby with New Hope Herp

  6. Hi, Shelby.. My RES well she’s very naughty, I can’t keep her Aquarium clean..she’s very dirty and knocks her filter over. She’s laying eggs for the 5th time. (Very concerned) not sure what route I should take, can you help me out?

    1. Hi!

      I would recommend at least a 75-gallon tank with a Fluval FX6 canister filter. It will definitely help with keeping the aquarium clean and the filter has really strong suction cups that will prevent your turtle from knocking it off all the time. As long as you are providing her with a nesting box and she is laying her eggs in that, you should be okay. It is that time of year for turtles to begin to get gravid. I would provide her extra calcium in the form of a Zoo Med Turtle Bone which will help with all of the calcium she is using to produce those eggs.

      As always, if you are concerned for your turtle please seek an exotic vet.

      I hope this helps!

      Shelby with New Hope Herp

  7. Hello Shelby! I was so happy to find your blog! I have 2) 18 year old RES. Collectively referred to as “the Turds”. After water that wouldn’t clear and some shell damage, I took them to a vet. “Bigger tank!” he said (mine was 30 gal- they grew!). So I purchased a 75 gallon and putting it together. For the bottom, I had fish gravel for many years (which they would sometimes eat and poop out) but now have river rock. With that big a tank it seems like too much weight to cover it completely. I am going to try the sand you suggested (thanks for the amazon link) with river rock random. I can’t wait to see how it all comes together and will send pics. My question, you mentioned to clean the sand first before set up. Can you advise on the best way to clean it? Thank you! Shelley and the Turds.

    1. Great job getting a 75-gallon tank! I know it can take up quite a bit of space but your turtles will really enjoy it. If you get the sand from the Amazon link you mentioned, you shouldn’t have to go overboard with cleaning it since it is pretty good quality sand and isn’t as dusty as others. To clean it, I would pour some in a 5-gallon bucket with some water and swish it around and then drain out the water. If you already have your 75-gallon tank filled with water, you can just get a small tupperware container and slowly lower the clean sand into the bottom of the tank.

      I hope this helps and yes, please send pictures!

      Shelby with New Hope Herp

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