Reduce them yourself. I believe in you.

With the solstice ignite mod, one shot would clear half the room when radiant. Polaris lance is pretty much the only weapon needed for that solo op. In the middle room, just shoot the diamond crystals and skate out of there. Unless you need lives, then kill champs... if theres an ammo crate on the top ledge, just use the ammo of that type and shoot all the crystals you can before picking up the crate. Mint and Boomslang are the weapons that I pair with polaris for it. Now that Solstice is ending, I guess I wont get my easy ignitions anymore, but it still isnt terribly difficult with a decent ad-clear build. If you dont want to use Polaris Lance, you could try Grav Lance (since its also a featured exotic), and while not solar, will make easy work of the clumps of red-bars. For old gear, Vision of Confluence with incandescent and EH or Paracausal Affinity (if not running prismatic with a lot of elements) is quite strong for that solo op.