does mulm, make mulm??? ( reproduce)

[Magnum Man]

so I have a 65 gallon tank that originally had Tilapia pairs / fry in it, and they are a dirtier fish, similar to gold fish… I just switched the tank over, rather than pulling everything down and starting over… so there was a good supply of mulm in the tank to start with…

the substrate is pebbles a single layer thick, I have good mechanical filtration , and have vacuumed up as much mulm as practical , on various water changes… the tank is very lightly stocked for me, with a colony of wild type swords in the tank, that are breeding like crazy, so lots of fry, that I’m assuming eat mulm, before they get big enough to eat the ground foods I feed… the tank is also full of the brown algae… so much mulm and brown algae, that it chokes out all my aquatic plants… I have several hoya vines growing out of the tank ( none are mature yet ) so the aquatic plants shouldn’t be starving for nutrients… every time I do a water change , I pull out bumper crops of mulm… it seems almost like it also reproduces like algae’s do???

 

[GaryE]

So what's mulm?

Fish poop, decaying leaves, dead plants, excess food - all of them mixed together. It isn't alive, but it's full of life, mainly bacterial.

Fish keep pooping, food goes in, plants die and break down, so mulm quantities grow. When I see what you're describing, I often check my filters to see if they're 'gunking up'.

One of my bad habits is to leave canisters all winter. I hate cleaning them, and it's so much easier to do it out in the yard when it's warm. It's getting into range and well overdue. A sign of Spring is me outside the fishroom fighting with the canisters.

I also find that I get a lot more mulm in tanks with terrestrial plant roots in them. I've wondered if they trap debris which then rots in their roots, producing fine particles that settle. I suspect the mechanical side of the filtration could remove a lot more without those root networks.

But it's a small price to pay for plants above the tanks.

 

[TwoTankAmin]

I want mulm in my planted tanks, it is plant food. But it is not sp much in the water as in the substrate as it sinks. I a well planted tanks which has a decent amount of pmants which are rooted in the substratem they eat the mulm basically.

I have neve done land plants with their roots in my tanks, I have never had any desire to do this. But I do have havilty planted community tanks. I rarely have to use my substrate ferts except for the very large plants which need this- swords, crypts etc.

Bear in mind that dead things which contribute to mulm are alse loaded with nitrogen in some form. I usually have at least 2 and usually 2 inched of substrate in well planted tanks depending in the tank size. My substrate basically become plant fertilizer from the mulm.

U think you issue may be dur to the use of land plants with their roots in the tank water. This lets them use the nutrients in the water but not those in the substrate. So, there is minimal use of the mulm and it accumulates,

@GaryE

I have a few canisters. I normally clean them twice year (in Dec. and Jun.) there is one exception an that is the one canister filter completely filled with 20 ppi Poret foam. it has a layer of floss at the top as it is needed to make wveything fit properly as much as filter out solids that make it through the two layer of foam. I was delinquint in cleaning it for only the second time in