I'm in the place to find crimson nirnroots and I've looked all over and can't seem to find any. I've tried killing stuff and seeing if it had any in them but I can't seem to find any that way. How do I get crimson nirnroots?
By the place where you find Crimson Nirnroots you mean Blackreach, correct?
If not, you can find it under the tower of Mzark. Alternatively, Alftland, Mzinchaleft and Raldbthar can also be used to access Blackreach
Once you're at the correct location, you can find Crimson Nirnroots in Sinderion's Laboratory along with the rest of the land, it's a matter of exploring and paying attention to the audio cue (chiming).
Alternatively, you may try to use this Map, which clues you to the location of clusters of the roots.
Crimson Nirnroots can only be found in Blackreach. They do not spawn on monsters, or in chests. Rather, they have to be harvested from Crimson Nirnroot plants on the ground.
Crimson Nirnroots are usually found near water.
While you certainly can get 30 Crimson Nirnroots in one go, you can also get it in two visits to Blackreach.
Blackreach respawns every 10 days, and Crimson Nirnroot also respawn. Therefore, you can get 15 Crimson Nirnroots the first visit, then wait 10 days, and then get 15 more Crimson Nirnroots.
best advice is to listen to the distinct sound the Nirnroot makes when your close, it's how I managed to find them.
You just have to look near the river in blackreach, if you still can't find any try leaving and doing some other missions therefore letting the cell respawn properly.