21% of 28 verified Waterbox Cube 20owners don't recommend it, and 1 describe specific problems — based on real owner comments from Reddit, enthusiast forums, and YouTube.
For balance: 75% recommend it. This page collects the complaints so you know what you're signing up for — read the full owner report for both sides. How we score
“the glass seems more suitable to reef system”— @keithberghoff4114 on YouTube
“don't get the wb cube20, its got a horrible baffle design and gets clogged all the time.”— bawse1 on Reddit
“I don’t see a protein skimmer. I thought this was the heart of any salt water aquarium.”— @timothyvandermeer6807 on YouTube
“whhhhhyyyy black silicone </3”— @ThatanOmega on YouTube
“i got my self a Cube 20 to and as i am in Europ im having problems getting a silent Pump as well :( I have a Jebao 1200, it seams working but ther is this DC snurring sound all the time,.. the Stock Pump is loud as well”— Rcfox on Nano-Reef Community
“My biggest issue at the moment is that I'm experiencing quite a loud buzz noise with the current pump (a Sicce Syncra Silent Water Pump 1.0). I feel this isn't acceptable (pretty disappointed really) and am pretty desperate to solve this issue”— Ekar on Nano-Reef Community
“Had it set up for two weeks and heard the tank crack and watched the crack grow from the outside of the tank”— @brookeviele1995 on YouTube
“Word of warning, the return pumps they provide are awful cheap and extremely loud”— @jokesaside9207 on YouTube
“waterbox is apparently really loose when it comes to build tolerances”— The_Lazy_Reefer on Bay Area Reefers
“Purchased the Waterbox cube 20 thinking it was AIO but it is not.”— westcoastwhale on Reef2Reef
“The stock pump is loud, which a DC would fix.”— >>klong<< on Reef2Reef
“mine loud asf at night”— @bandthesupremefishguy8665 on YouTube
Not complaints — practical notes from owners that didn't affect the score.
“I have the cube20 and when I tried to upgrade my return pump the flow into the back of the tank couldn’t keep up. Went back to the stock pump and added a random flow generator to it instead.”— SrGearhead on Reddit
“I haven't gotten anything more than some green spot algae on the glass here, which is amazing. The fish are getting bigger and look to be doing great.”— evil8 on The Planted Tank Forum
“The pump that came with it is a little noisy so going to get a Sicce 1.0 pump and see if it is quieter.”— msummerf on Nano-Reef Community