New to the hobby - questions about sand substrate

Hello everyone!!
So, I have a 35 gallon tank with gravel substrate and I have 3 cories, one Bristlenose pleco and 3 kuhli loaches.
I used to have sand substrate, but I had a huge (really huge) problem with anaerobic bacteria. The aquarium was smelling like bad gas (or rotten eggs), so I immediately switched to gravel (rough, about 1 cm).
I used to have 10 kuhlis but I lost almost all of them. I spent almost a month searching for a reason, but so far, no success. During this time, I was extremely upset, I almost gave up. But since I still had fishes, I decided to keep them.
I am determined to keep kuhlis but as far as they are comfortable and safe, so I am thinking about switching to sand substrate. I'm afraid of having the same issue as I had before, that's why I am asking you guys for advice. So here are my questions:
- Is it possible to cover my gravel with sand? I heard that the sand will go beneath the gravel.
- If it isn't, can I replace the gravel in a stablished aquarium? Won't I have the same mistakes I've had before with sand substrate? From what I know of using a lower height substrate can mitigate the issue, as I used to have almost 6 to 7 cm.
- My kuhlies weren't eating (as far as I know) and were in constant hiding (and still are). I have a moderate planted aquarium with low-tech plants, but I think I could create more hiding places.
Thanks guys, sorry for the long post!

 

Is It A Kuhli Loach?

 

Is It A Kuhli Loach?

Yes, they are!

 

Then Do These Steps:
1)Change The Water, Remove Any Substrate(If u want less trouble handling the tank)
If U Use Substrate, Do Weekly Once A Water Change
Please Wash The Substrate Water In Some Container 3 Times Before You Use For The Next Water Change.

2)Before Dropping The Fish Into The Water, Apply Stress Heal and let it settle for around 15-20 minutes(Depends On The Size Of The Tank)
3)If Any Worms Present In The Kuhlies, Then Apply Worm Out and let it rest for 15-20 minutes
4)Drop-In The kuhli. Let It Aquamate For 1 hour
5)Finally Drop Some Food. It Will Finally Eat!
I Recommend To Increase The Immunity Of the kuhli Using Some immunity Booster Food Available online(Take From Trusted Sellers)

 

Then Do These Steps:
1)Change The Water, Remove Any Substrate(If u want less trouble handling the tank)
If U Use Substrate, Do Weekly Once A Water Change
2)Before Dropping The Fish Into The Water, Apply Stress Heal and let it settle for around 15-20 minutes(Depends On The Size Of The Tank)
3)If Any Worms Present In The Kuhlies, Then Apply Worm Out and let it rest for 15-20 minutes
4)Drop In The kuhli. Let It Aquamate For 1 hour
5)Finnaly Drop Some Food.It Will Finnaly Eat!
I Recommend To Increase The Immunity Of the kuhli Using Some immunity Booster Food Available online(Take From Trusted Sellers)

So what you are saying is that the kuhli were stressed and that's why they weren't eating? If so, do you have any idea why they were stressed?
Would you recommend changing the substrate? Or adding more hiding spots?

 

Any Fish If They Are Stressed They Won't Eat. To Understand This I'll Give U An Example.
Let's Say You Are Awake In Midnight And u Are Stressed And Hungry, Most Likely U Have Some Loss Of Appetite. Same Thing For Them Except They Are More Sensitive Than Humans. So They Have A Loss Of Appetite
Second, When Water Quality is poor, They Get Stressed(Like U In A Stinky, Smelly Room).
Gravel And Sand(In Terms Of Water Condition) Doesn't Make Much Difference. If You Have Substrate, Then I Recommend Weekly Once Water Changes.
If You Don't Want To Do Weekly Once Water Change And Do It Monthly Once, Then Remove The Substrate U Are Using.
If U Want Your Fish To Have Some More Fun, Then Yes, You Can Add More Hiding Spot, But Please Make the Hiding Spots As Much Substrate-Free As Possible As Some Fish Have A Tendency To Make It A Toilet For Them(I Know It Is Gross, But True.).If Not Removed, Causes Water Contamination
But Please Remove Substate Before Any Treatment

And Some Worm Diseases Also Known Contribute To Loss Of Appetite(at Atleast That's What Happened to my Flowerhorn)

 

Any Fish If They Are Stressed They Won't Eat. To Understand This I'll Give U An Example.
Let's Say You Are Awake In Midnight And u Are Stressed And Hungry, Most Likely U Have Some Loss Of Appetite. Same Thing For Them Except They Are More Sensitive Than Humans. So They Have A Loss Of Appetite
Second, When Water Quality is poor, They Get Stressed(Like U In A Stinky, Smelly Room).
Gravel And Sand(In Terms Of Water Condition) Doesn't Make Much Difference. If You Have Substrate, Then I Recommend Weekly Once Water Changes.
If You Don't Want To Do Weekly Once Water Change And Do It Monthly Once, Then Remove The Substrate U Are Using.
If U Want Your Fish To Have Some More Fun, Then Yes, You Can Add More Hiding Spot, But Please Make the Hiding Spots As Much Substrate-Free As Possible As Some Fish Have A Tendency To Make It A Toilet For Them(I Know It Is Gross, But True.).If Not Removed, Causes Water Contamination
But Please Remove Substate Before Any Treatment

And Some Worm Diseases Also Known Contribute To Loss Of Appetite(at Atleast That's What Happened to my Flowerhorn)

I understand... But yeah, I do a weekly maintenance, I normally do water changes and vaccum cleaning the substrate.
But I will try to sort something, obviously following your advice!
Do you know how to prevent anaerobic bacteria from forming at the substrate? Maybe a shallower substrate?
Thanks a lot!

 

Replace the gravel with sand, and get some Malaysian trumpet snails to keep it stirred up. That should eliminate problems with gas building up in it.

 

Welcome to Fishlore

You can prevent the buildup of gas in sand by keeping it aerated. Stir it from time to time. I stir mine with each weekly water change. I also had assassin snails living in my sand. They did a fine job of keeping it stirred. I removed the assassins when I got mystery snails. Malaysian Trumpet Snails will do the same thing.

Elbert, that handsome fellow over there in my avatar helps me keep the sand stirred too. Your loaches should help keep it stirred too. The sand in my tanks is less than 2inches (5cm) deep. A bamboo skewer would be a good tool to have to help you stir the sand. Just swirl it through the sand with each water change. You will have to be careful around plant roots but you should be able to stir it enough to prevent pockets of gas.

BTW: I have pool filter sand in my tanks. It doesn't pack as hard as some types of sand. The size of the sand you use does make a difference. The smaller the grain size the tighter it will pack.

 

Replace the gravel with sand, and get some Malaysian trumpet snails to keep it stirred up. That should eliminate problems with gas building up in it.

OK, I will search for it. Thank you very much!!

Welcome to Fishlore

You can prevent the buildup of gas in sand by keeping it aerated. Stir it from time to time. I stir mine with each weekly water change. I also had assassin snails living in my sand. They did a fine job of keeping it stirred. I removed the assassins when I got mystery snails. Malaysian Trumpet Snails will do the same thing.

Elbert, that handsome fellow over there in my avatar helps me keep the sand stirred too. Your loaches should help keep it stirred too. The sand in my tanks is less than 2inches (5cm) deep. A bamboo skewer would be a good tool to have to help you stir the sand. Just swirl it through the sand with each water change. You will have to be careful around plant roots but you should be able to stir it enough to prevent pockets of gas.

BTW: I have pool filter sand in my tanks. It doesn't pack as hard as some types of sand. The size of the sand you use does make a difference. The smaller the grain size the tighter it will pack.

Thanks!! I'm sure Elbert is very handsome despite the avatar being so small to see more details.
Well, I hope I find some good guy like Elbert to help me out.

Do you people know how to care for kuhli loach? I did some research and I found that they are very easy, but since I lost almost all of them, I don't think so. Maybe a sand substrate and more hiding places could solve the problem?

 

Just Make Sure Your Pump Can Grap All The Waste The Fish Produces. Every 2 Weeks Replace The Filter Or If It Is Reusable, The Clean And Place It Back.

"Fish keeping can have ups and downs just like life, but except looking after yourself, you're looking at some other creature" - me

 

Replace the gravel with sand, and get some Malaysian trumpet snails to keep it stirred up. That should eliminate problems with gas building up in it.

Good name change, I wondered what you'd make it!

 

Just Make Sure Your Pump Can Grap All The Waste The Fish Produces. Every 2 Weeks Replace The Filter Or If It Is Reusable, The Clean And Place It Back.

No, do not replace the filter every two weeks. Even if it's the filter cartridge, and the manufacturer says to replace it often, don't do it. Rinse it and put it back until it's absolutely falling apart, and even then, leave it in the filter along with the new one for a few weeks so you don't remove so much of the beneficial bacteria.

 

Just Make Sure Your Pump Can Grap All The Waste The Fish Produces. Every 2 Weeks Replace The Filter Or If It Is Reusable, The Clean And Place It Back.

Yeah, but I think cleaning the filter would be better. But nice point!

No, do not replace the filter every two weeks. Even if it's the filter cartridge, and the manufacturer says to replace it often, don't do it. Rinse it and put it back until it's absolutely falling apart, and even then, leave it in the filter along with the new one for a few weeks so you don't remove so much of the beneficial bacteria.

Yeah that's what I thought.
I won't have problems with beneficial bacteria if I change the substrate, will I?

 

Yeah, but I think cleaning the filter would be better. But nice point!

I agree.

Yeah that's what I thought.
I won't have problems with beneficial bacteria if I change the substrate, will I?

In a well established tank changing the substrate will have minimal affect on your cycle. Although you are removing some bacteria there should still be enough on filter media and decor to prevent a mini-cycle.

but....

If this is a new tank and hasn't had time to get firmly established you may experience a slight rise in ammonia and possibly nitrites. Be prepared to do water changes should either rise above .25 or so. The bacteria you will be removing should be quickly replaced.

 

I agree.

In a well established tank changing the substrate will have minimal affect on your cycle. Although you are removing some bacteria there should still be enough on filter media and decor to prevent a mini-cycle.

but....

If this is a new tank and hasn't had time to get firmly established you may experience a slight rise in ammonia and possibly nitrites. Be prepared to do water changes should either rise above .25 or so. The bacteria you will be removing should be quickly replaced.

OK then. Good to know!
Thanks a lot!!!

 

What do yall think of, after the sand is washed, it gets a chance to'mingle' with the gravel before being added to inoculate it with the successful biome? The sand may take some turbulence to settle into the cracks between gravel, which puts you at risk for Pockets Of Putrescence again. Heres what I would do, based on what I did with the semi-aquatic bamboo I have going in about six inches of sand. (for background, there are some quarter sized pebbles, a coarse sand, and a finer sand, with the bamboo rooted an inch deep, with some air pockets here and there, it was all planted about a month ago... anyway!)
First off, it seems like most ways you go, youll be taking out the current substrate. Do the usual cleaning and such (or skip if its not needed, just follow your usual routine to minimize change). Then I would wash the sand, only because i forgot to mention that as the actual first step. Then mix the two substrates, it may be easier to mix them when theyre dry, but that takes time and could kill the biome on the substrate. Heres the important part that is the solution (in my opinion, from what I have observed based on little experience).
When youre ready to put the substrate back, make sure to pour it while under water, and let it spread out enough that air cant be trapped between the particles, only water.I believe that I trapped air bubbles in the sand when repotting by adding sand then water on top, so the sand grains were too tight and close together to let the bubbles float. If air bubbles appear after that, I might give a section a little harassment to smell the bubble for anything yucky. If it smells like what your tank smelled like with the gravel, then the air bubbles are fine to leave, the same reactions were happening in the gravel, the difference is that the sand is less permeable. If it smells bad, then thats bad and youll have to repeat the substrate switch.
For extra caution, I would consider washing the sand with a disinfectant (bleach, peroxide, ammonia, someone else knows) first thing, then make sure its rinsed VERY well.
On substrate textures: particle size can have an effect on how well the same locks together, but the coarseness (stabbiness of grain shape, not grain size) has a lot to do with it as well. Things with corners pack together tight, round things pack loose. Soft, round grains may be better for releasing air bubbles than sharp, angular sand even if they are the same size grain. I found adding a finer sand to the coarse larger grain sand helped fill the spaces where gasses collect and helps things move around more, like ball bearings. Congrats if you made it through all that and thanks for reading!!

 

What do yall think of, after the sand is washed, it gets a chance to'mingle' with the gravel before being added to inoculate it with the successful biome? The sand may take some turbulence to settle into the cracks between gravel, which puts you at risk for Pockets Of Putrescence again. Heres what I would do, based on what I did with the semi-aquatic bamboo I have going in about six inches of sand. (for background, there are some quarter sized pebbles, a coarse sand, and a finer sand, with the bamboo rooted an inch deep, with some air pockets here and there, it was all planted about a month ago... anyway!)
First off, it seems like most ways you go, youll be taking out the current substrate. Do the usual cleaning and such (or skip if its not needed, just follow your usual routine to minimize change). Then I would wash the sand, only because i forgot to mention that as the actual first step. Then mix the two substrates, it may be easier to mix them when theyre dry, but that takes time and could kill the biome on the substrate. Heres the important part that is the solution (in my opinion, from what I have observed based on little experience).
When youre ready to put the substrate back, make sure to pour it while under water, and let it spread out enough that air cant be trapped between the particles, only water.I believe that I trapped air bubbles in the sand when repotting by adding sand then water on top, so the sand grains were too tight and close together to let the bubbles float. If air bubbles appear after that, I might give a section a little harassment to smell the bubble for anything yucky. If it smells like what your tank smelled like with the gravel, then the air bubbles are fine to leave, the same reactions were happening in the gravel, the difference is that the sand is less permeable. If it smells bad, then thats bad and youll have to repeat the substrate switch.
For extra caution, I would consider washing the sand with a disinfectant (bleach, peroxide, ammonia, someone else knows) first thing, then make sure its rinsed VERY well.
On substrate textures: particle size can have an effect on how well the same locks together, but the coarseness (stabbiness of grain shape, not grain size) has a lot to do with it as well. Things with corners pack together tight, round things pack loose. Soft, round grains may be better for releasing air bubbles than sharp, angular sand even if they are the same size grain. I found adding a finer sand to the coarse larger grain sand helped fill the spaces where gasses collect and helps things move around more, like ball bearings. Congrats if you made it through all that and thanks for reading!!

Well, that's some good advices!!
Thanks for sharing!! Definitely helped!