I have about 90% coverage in my 55gallon with microswords. I use 100% fluorite substrate. I started out with just 4 or 5 clumps and stuck them into substrate about 1/3 to 1/2 of length and they have grown in over time. Do you have fish pulling them up? Occasionally I get a runner that floats and I just cut it off so it does not pull on the rest of the plants it is connected to.