The tile basically says it all. How do you clean the substrate with a carpet of dwarf hairgrass? I have 1 nerite snail and 2 amano shrimp which will help but will not be enough to completely clean the entire 30 gallon tank substrate.
You can't gravel vac where there is dwarf hairgrass. But that's okay as anything that collects there is just organic fertilizer for the plants. Remember, once organic material completely decomposes, the resulting mulm is relatively inert.
I have pool filter sand substrate and Malaysian Trumpet snails - With the exception of moving rooted plants, I haven't touched the sand in over 8 years!