MULM question

[Marnol D]

I have a tank that has a ton of mulm build up on the top level of sand (i dont gravel vacuum as the tank has rooted plants and grasses that run everywhere). I usually dont mind the mulm (as it used to be hidden) but I just rescaped the tank and the mulm has gone everywhere. Is there a gravel vacuum or some product/idea that would let me cycle the mulm off the top layer of sand and water (as the filter does) and strain the mulm out of the water and return the water back to the tank as I vacuum the mulm out? Or since the substrate of sand is only an inch deep should I just add more sand over the mulm to hide it?

I guess I could take a fine mesh/strainer and hold it over the tank as I use a siphon pump to cycle the water and catch the mulm in the strainer. But is there any product like this that may be easier to use/ not make a mess when I inevitably shoot water all over the place. I would rather not pump a ton of water out and then add new water in as I tend to have a mass shrimp die off whenever I do a traditional water change instead of just topping the evaporation off and re-mineralizing the water. 

The tank is heavily planted in most areas with root plants and now a massive bundle of low growing wisteria java fern being the center piece and duck weed at the top so nitrate isnt an issue >5 ppm  and the tank reads 0 for ammonia and nitrite along with co2 being pumped into the tank. 

As for filtration I run two sponge filters (a coarse coop one and a finer one ,this one stays off during the day for co2 to run) along with a power head with a coarse sponge on it to cycle the water. The inhabitants of the tank do not kick the mulm up so it stays put on the substrate. Shrimp/snails/ two peapuffers/neon tetras and guppies.

[Dwayne Brown]

I would recomend that you get a peacock goby. I have one they are laid back and relitively hardy. And the best part about them is that their diet consists of mulm. I dont have any mulm from the gobys constant eating so I feed him algea waffers. They get around 3 inches long I was able to find one at my lfs but it was only 15 dollars.

Edited March 26, 2021 by Dwayne Brown

[H.K.Luterman]

They have stuff like this if you do Google searches for gravel vacs. Battery operated and there's a mesh that's supposed to catch the dirt/mulm. I don't know how well they work though.

[Brandy]

Suggestion: Siphon out the mulm to a bucket (swirl your siphon hose gently just above the mulm). Lift the bucket to a counter top. wait 10-20 min for the mulm to settle to the bottom of the bucket. siphon just the clean water to another container and return to the tank. It might need to be repeated a few times to get it all.

[Brandy]

39 minutes ago, Dwayne Brown said:

I would recomend that you get a peacock goby. I have one they are laid back and relitively hardy. And the best part about them is that their diet consists of mulm. I dont have any mulm from the gobys constant eating so I feed him algea waffers. They get around 3 inches long I was able to find one at my lfs but it was only 15 dollars.

Can you post pic or a link to the fish you mean? There is a peacock gudgeon that is also called a goby sometimes, but I didn't think it ate mulm or algae, but instead ate meatier foods? 

[Daniel]

Also in my experience, mulm tends to be the place where the tiniest of shrimp hang out.

 

[Dwayne Brown]

11 minutes ago, Brandy said:

Can you post pic or a link to the fish you mean? There is a peacock gudgeon that is also called a goby sometimes, but I didn't think it ate mulm or algae, but instead ate meatier foods? 

[Brandy]

11 minutes ago, Dwayne Brown said:

Aaah, I think this is a rainbow stiphodon goby, which is reported to eat biofilm...VERY COOL! Thank you @Dwayne Brown!

[Littlefish]

Get the cheap Wallmart pillow stuffing used as polishing floss in reef tanks and siphon water over it into a 5g bucket.

[Patrick_G]

I like all the ideas posted and I’ll add two more. How about a second circulation head to stir things up and get the mulm headed to the filter? Some Corys might also accomplish the same thing.

I can empathize with this situation, I just spent about 20min using airline tubing to siphon detritus out of my little Nano shrimp tank. 

[Marnol D]

Thank you all for the suggestion! 

[Streetwise]

I love mulm. I will admit that I have cleaned filters and dumped all the mulm back into the tank.

[CalmedByFish]

Isn't mulm the "mud" that root-feeding plants eat? I don't actually understand whether or not it's desirable to have.

 

[DShelton]

40 minutes ago, CalmedByFish said:

Isn't mulm the "mud" that root-feeding plants eat? I don't actually understand whether or not it's desirable to have.

 

Mulm is indeed 'good' it is a haven for beneficial bacteria, paramecium, etc.

[Marnol D]

2 hours ago, Streetwise said:

I love mulm. I will admit that I have cleaned filters and dumped all the mulm back into the tank.

@Streetwise I find it useful in a tank and it does amazing things for plants. I just have black sand so the light brown contrasts with it awful and it’s such a fine powder it won’t sink under the sand. 

[Streetwise]

You could scatter a bit of gravel so that you have a continuum of sizes.

[CalmedByFish]

1 hour ago, DShelton said:

Mulm is indeed 'good' it is a haven for beneficial bacteria, paramecium, etc.

That's the first time I've heard "paramecium" outside of The Princess Bride. Haha!

So if mulm is good, why in the world do we vacuum gravel? 

[Dwayne Brown]

 

1 hour ago, CalmedByFish said:

That's the first time I've heard "paramecium" outside of The Princess Bride. Haha!

So if mulm is good, why in the world do we vacuum gravel? 

We vacume gravel for a variety of reasons for me I have a sand aquarium and the mulm can look very unsightly so I do it for looks. I also do it to prevent a build up of decaying organic matter on and in the sand in order to prevent ammonia spikes.

[Hobbit]

1 hour ago, CalmedByFish said:

So if mulm is good, why in the world do we vacuum gravel?

Two reasons that I can think of: First, to most people it looks “dirty” so they want to get rid of it. Second, if you don’t have a planted tank, there’s nothing to use up the nutrients and those excess nutrients can feed algae. Algae also looks “dirty” to most people, so they don’t want that either. 😄

[Jennifer V]

@Streetwise @Brandy@Daniel @Hobbit so I'm confused -- it doesn't take much for this to happen 😆 I have quite a bit of mulm in my new tank. I accidentally added it when I transferred water from an older tank, which is a whole other story. The tank currently has bladder snails, but I just added a few shrimp a couple days ago. I only have epiphyte plants in the tank so nothing to absorb the nutrients from the mulm. Tank parameters are 0 Ammonia 0 nitrite, ~10 nitrate. Black sand substrate but I don't really care about the look of the mulm on top.

Should I just not worry about it? Should I suck up a bit of it and top off the tank?

I don't want to do a water change yet because of the shrimp. I also don't want to create and ammonia situation because of the shrimp. 

Bad mulm? Good? I don't know! 

Side note: @Brandy the shrimp are currently in the portal to another dimension because I can't find them anywhere. Ha! 

 

Edited April 15, 2021 by Jennifer V
More info

[Daniel]

The shrimp could be hiding in mulm.🙂

If the mulm is unattractive, it is easy to siphon out. But given your concerns about water changes etc...I am not sure. Mulm isn't bad, but isn't that wonderful either. The best thing for me is it has been a good place to shelter baby fish, baby shrimp and infusoria. If it bothers you, nags at you, you should get rid of some it and see how that feels.

[Hobbit]

Old mulm won’t mess up your water parameters at any appreciable speed—it’s more of a slow-release. (Like, really slow.) So I wouldn’t worry about it. Plus I’m sure the shrimp are enjoying eating the biofilm off it!