Need help on choosing a substrate

[Jeff-Ft-Lauderdale]

Video link - https://photos.app.goo.gl/3CzxWx1eNGEQtwDfA

So I bought a new condo in Ft Lauderdale and inherited a mature marine aquarium. Which is great, because I always wanted one anyway, and am glad I don't need to set one up from scratch. I have a lot of experience with Freshwater tanks of all sizes (well, up to 55 gallons). But I have never actually had a saltwater tank before.

This picture is what it looks like (looks bluer than it actually is...the video is more accurate).

It is a 50 gallon wedge tank. The bottom is bare, but the tank is very healthy with no problems (nothing is sick, fish all get along, nothing is eating anything else).
It contains:

3 small clown fish​

3 corals (he told me the species, but I forgot)​

At least 2 rose Anemones (previous owner says he saw 3 though, but I've only located 2)​

1 shrimp (Banded coral shrimp? If not, it looks similar to that, like 2 or 3 inches)​

3 starfish - forgot the species, but they are the small kind (you can see one in the bottom left of the video) - I think 2 of them are brittle stars, but I never see them in the open​

A few small hermit crabs (like 1 cm or so) and small snails.​

​

Right now the tank is bare but I'd like to put in a little substrate, mostly just for aesthetic value. I had never heard the terms "living water" and "living sand" before now (though I knew what living rock was). I get living water here locally. He suggested I buy live sand online.

So here are my questions:

1) My preference is for black sand. He said that would be a good choice but warned me that people have complained that metallic particles in the sand can get stuck under the magnetic brush I use to clean the glass...that this will score the plexiglass over time. If this is an insurmountable problem, I am willing to use a different sand type (the glass is reasonably intact, but it's not new and I don't want to make it any worse). But I'd really like to use black. Doing some quick research online, I saw that people were recommending "authentic" Hawaiian sand since it is lava based with no metals in it. Is this legit? If so, where can I buy it?

2) Is there any real difference between marine and freshwater live sand? Is one safer than the other? Will it provide food for the hermit crabs and the shrimp with food? Should I get an additional filter feeder for the sand?

3) What are the chances of introducing disease or parasites into the aquarium by doing this? I assume it is probably not high, since he has been using living water for years already. But I am new at this and want to be careful.

Thank you.

 

[PeterC99]

First - Welcome to R2R!

How long has this aquarium been setup and what do you think your long-term goals are? Successful aquariums have very delicate balances. There is much to learn and would recommend getting to know your aquarium and taking the time to learn how to keep a successful saltwater aquarium before making major changes.

Good Luck!

 

[blaxsun]

Everything you've been told about the Hawaiian black sand is correct, with the exception of the "authentic" Hawaiian sand (it too would have metallic particles because it's volcanic in nature). If you like the black sand from an aesthetic standpoint you should go with that. As long as you're not running your magnetic scraper into the sandbed itself you should be fine.

Since your tank is already established you don't need to worry about the "live sand" aspect, so be sure to rinse thoroughly before use and let dry completely before adding to your tank. As @PeterC99 pointed out - you already have an equilibrium in the tank - so adding a layer of substrate could affect this balance over time. You may need to expand your cleaning crew to include sand-sifting variants like nassarius snails, conches and cucumbers.

If you rinse/clean/dry your sand properly there's almost no chance of introducing something to your tank aside from some stray beneficial bacteria (live rock is something different entirely).

Also note that the black sand is larger in size and isn't well-suited for sand filtering fish like gobies, jawfish, etc.
..........

In my 200-gallon system I use CaribSea Oolite. It's super-white, reflective and absolutely gorgeous. It also gets stirred up by a stray fish fart, so just a fair warning that it's more maintenance!

 

[Jeff-Ft-Lauderdale]

How long has this aquarium been setup and what do you think your long-term goals are? Successful aquariums have very delicate balances.

I do not know the exact amount of time, but I know it's at least several years. He did warn me that clownfish typically occupy tanks only in pairs, but these 3 have been getting along. If it becomes a problem, I can remove one of them in the future.

Honestly, I already like it a lot as it is. The changes I want to make are minor (like this sand). This might change a year from now when the novelty of having a marine aquarium has worn off and I am more knowledgeable. Right now I want to keep it easy-mode. I have no plans to add additional fish (these clown fish are small, but I've been told they will grow to 3 or 4 inches eventually), except maybe a small filter feeder. I am being really careful not to overfeed.

Marine fish are great, but the real appeal of marine tanks for me has always been stuff like corals and anemones. There's really no analog to those in the freshwater world. So they are still new and novel to me. If I was going to add anything in the future it'd be those. I know that salt water holds a lot less oxygen than freshwater, but have been told that these will have little or no impact on oxygen resources. I will not be adding anything the near future though (including these). Not until I know what I'm doing. In the near future I mostly just want to keep the tank healthy as-is. The only thing I want to add right now is substrate.

There is much to learn and would recommend getting to know your aquarium and taking the time to learn how to keep a successful saltwater aquarium before making major changes.

Yeah, that's why I am being careful. This kinda fell in my lap and I am grateful I don't have to start it from scratch. I don't want to screw it up.

 

[PeterC99]

I do not know the exact amount of time, but I know it's at least several years. He did warn me that clownfish typically occupy tanks only in pairs, but these 3 have been getting along. If it becomes a problem, I can remove one of them in the future.

Honestly, I already like it a lot as it is. The changes I want to make are minor (like this sand). This might change a year from now when the novelty of having a marine aquarium has worn off and I am more knowledgeable. Right now I want to keep it easy-mode. I have no plans to add additional fish (these clown fish are small, but I've been told they will grow to 3 or 4 inches eventually), except maybe a small filter feeder. I am being really careful not to overfeed.

Marine fish are great, but the real appeal of marine tanks for me has always been stuff like corals and anemones. There's really no analog to those in the freshwater world. So they are still new and novel to me. If I was going to add anything in the future it'd be those. I know that salt water holds a lot less oxygen than freshwater, but have been told that these will have little or no impact on oxygen resources. I will not be adding anything the near future though (including these). Not until I know what I'm doing. In the near future I mostly just want to keep the tank healthy as-is. The only thing I want to add right now is substrate.



Yeah, that's why I am being careful. This kinda fell in my lap and I am grateful I don't have to start it from scratch. I don't want to screw it up.

Much to learn about the chemistry and nutrients in your aquarium. Sounds like the previous owner knew what he was doing and has everything in balance.

Having a bare bottom aquarium is really ideally for many acro corals. Allows you to have tremendous flows. Something g to think about.

 

[Jeff-Ft-Lauderdale]

Everything you've been told about the Hawaiian black sand is correct, with the exception of the "authentic" Hawaiian sand (it too would have metallic particles because it's volcanic in nature). If you like the black sand from an aesthetic standpoint you should go with that. As long as you're not running your magnetic scraper into the sandbed itself you should be fine.

Awesome, thank you. I suppose I can get a long brush and just brush it manually once a week down there.

Since your tank is already established you don't need to worry about the "live sand" aspect, so be sure to rinse thoroughly before use and let dry completely before adding to your tank. As @PeterC99 pointed out - you already have an equilibrium in the tank - so adding a layer of substrate could affect this balance over time. You may need to expand your cleaning crew to include sand-sifting variants like nassarius snails, conches and cucumbers.

I will do that. It never occurred to me to add a conche...I actually like those a lot. I will explore getting nassarius snails too.

I was not planning on adding a lot. Like 5lbs. Definitely less than 10. Just enough to cover the bottom. There is a bio-ball cannister in the base of the stand that is hooked into the filtration that isn't showing the the photos.

If you rinse/clean/dry your sand properly there's almost no chance of introducing something to your tank aside from some stray beneficial bacteria (live rock is something different entirely).

Will rinsing and then baking it work? If I really don't need living sand, that will simplify this a lot I think.

Also note that the black sand is larger in size and isn't well-suited for sand filtering fish like gobies, jawfish, etc.

Good to know. I have no plans to add any other fish at this point. If the filter feeders above are enough.

 

[blaxsun]

Awesome, thank you. I supposed I can get a long brush and just brush it manually once a week down there.

I will do that. It never occurred to me to add a conche...I actually like those a lot. I will explore getting nassarius snails too.

I was not planning on adding a lot. Like 5lbs. Definitely less than 10. Just enough to cover the bottom. There is a bio-ball cannister in the base of the stand that is hooked into the filtration that isn't showing the the photos.

Will rinsing and then baking it work? If I really don't need living sand, that will simplify this a lot I think.

Good to know. I have no plans to add any other fish at this point. If the filter feeders above are enough.

Nassarius are mainly nocturnal. There are a few varieties, but any would do great in your tank. I've tried sand-sifting starfish but they don't seem to survive more than a year.

Cucumbers are probably the most efficient (dirty sand in one end - clean sand out the other), and they worked great with the black sand I had in my two previous tanks (larger size wasn't an issue). Note that there can be an issue with some cucumbers becoming toxic if killed, which is why I've stuck with the black cucumbers (they spew an extremely sticky web if provoked and then go back to doing their thing).

Rinsing and baking certainly works (I've baked in the past, which was probably overkill). Sun or air dry is probably more than sufficient. Living sand is there really to help with cycling new tanks, so you won't really be getting the full benefit. And you have to put the living sand in as is - which is going to cloud and mess up your tank and equipment for a few days. I'd stick with rinse and dry.

Some nassarius snails, conches and probably a few blue or scarlet hermit crabs would be a great addition. The black sand will also "hide" the typical stuff you'd see in a white sandbed to some extent, so that it's not quite as visible.