I have moss as the top substrate layer in two of my bioactives (a 40 gallon and 18 x 18 x 24, both currently uninhabited) but it’s started to turn white on the top layer which I’ve read is from drying out. It also darkens in color and I personally don’t love the look of it. I was researching online and I came across some articles about growing live sphagnum moss. Has anyone grown live sphagnum moss or have any tips for growing it? Has anyone tried this in their bioactive tanks? I would still have leaf litter on top and I was wondering if I could keep different mosses next to each other or would one outcompete the other?
I also want to know what @ghoulishcresties and @foxreptile think of this since they have a good understanding of bioactive tanks.
I have it in my vivs as it’s mixed in with the substrate.
You can either buy it live or ‘dry’. Which is fine but I’ve found soaking it first is best or it’s very dusty!
Basically keep it moist and either is ok!
And yes you can keep multiple types together, you just cut it back. We have multiple moss types in with the darts and Williamsi. 
That’s great! I’m going to try to get some at a plant store or at the next reptile expo. Do you have a picture of the mosses in the dart and Williamsi tank?
Christmas moss
Java Moss
There’s also subwassertang moss also in them.
And also different types of sphagnum! Including a red one
I tried growing moss, but I didn’t do well with it so I just use garden sphagnum moss mixed in.
I plan to try again though as I think it was the place I got them from (a few other plants also died off).
You may also look into pillow moss, Zoo Med even sells a good amount for fairly cheap, as Frog Moss. I like it much more than most of the sheet mosses I’ve used, they do pretty what you described in my experience. The pillow moss I’ve even been able to pull little parts out of and put into holes in cork, and it does pretty well. I’ll show you some examples of it when I’m around some of my vivariums later on today.
Those look great, I think I might use different types in different places and maybe remove ones I don’t like.
This can be a result of excess nutrients as well.
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I have grown it for my carnivorous plants, but never as part of a bioactive tank. It is fairly simple to grow, just keep it moist enough and it tends to do its own thing
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Once sphag establishes, it can be an extremely hardy and prolific grower so I would not be surprised if it eventually swarms over other mosses in the tank