Resonance Potions are EXP materials that can be used to level up Resonators (characters) in WuWa. With so many waifus and husbandos to build, you're going to need a lot of Resonator EXP materials to get everyone to level 90. Here are all the ways you can get Resonance Potions in Wuthering Waves.
How to farm Resonance Potions in Wuthering Waves
Simulation Training (farming)
There are plenty of ways to obtain Resonance Potions in the game, but the fastest way is by farming for them in the Simulation Training room. Head to the area circled above at the north of Jinzhou. Speak to Yhan and choose Resonance Potion to enter a Sonoro Sphere (Domain) where you must defeat a few waves of enemies.
Once the enemies are defeated, spend x40 Waveplate (Resin/Energy) to obtain Resonance Potions, Union EXP, and other rewards. The number of Resonance Potions you get depends on the Sonoro Sphere's level, which increases as you level up your SOL3 Phase (World Level).
Quests
Wuthering Waves houses a collection of Main Quests, Companion Stories, Exploration Quests, and Side Quests, all of which grant you some Resonance Potions as rewards. I strongly recommend completing Quests as some are prerequisites to others, while others may trigger the discovery of new mechanics.
Dailies (Activity)
We all hate dailies—but we can't deny that they are rather rewarding. By completing dailies in Wuthering Waves, you can collect a plethora of upgrade materials, including Resonance Potions. You can access the Activity page via the Guidebook in the Terminal or the upper right of the screen.
Milestones
You can find the Milestones page in the Guidebook, accessible via the Terminal or the upper right of the screen. These are early-game challenges that grant you a lot of amazing rewards to help jumpstart your journey.
Apart from Resonance Potions, you'll also get Astrites (premium currency), Shell Credits, Union EXP, Echos, and other upgrade materials, so I strongly recommend completing these Milestones whenever you're not sure how to progress.
Points Shop
Head to the Store menu via the Terminal, then select the Adversity Exchange section of the Points Shop. Here, you can spend Hazard Records obtained from completing challenges in the Tower of Adversity. The game mode is similar to Genshin Impact's Spiral Abyss, and every Crest (Star) you get will reward you with a few Hazard Points to spend in this dedicated shop.
I personally recommend saving your Hazard Records for better items, but they are useful for getting a few emergency Resonance Potions on a desperate day.
Should you spend Resonance Potions right away in Wuthering Waves?
Resonator levels are blocked until you increase your SOL3 Phase (World Level), so your use of Resonance Potions will gradually increase at a reasonable pace. However, resources are generally scarce for free-to-players in the early game, as the only way to farm a large number of Resonator EXP materials costs Waveplates, which take time or money to replenish.
I recommend pulling a few times in the gacha and playing around with different Resonators before committing to a core team of three. This should ideally include your favorite waifu or husbando, a reliable DPS, and your first five-star Resonator from the targeted banner, which will provide a welcome power boost for your team. This core team will be enough to carry you through the first week or so of gameplay, which will buy you enough time to farm more resources to build other characters.
For guides on the best Resonators to choose from in WuWa, check out the Best standard five-star Resonator to pick in Wuthering Waves here on Pro Game Guides.
