I lost 2 Zebras after I did a water change and refilled it up higher than the top lip of the Lily pipe.
Even with a non CO2 tank, a Rena XP 3(300-350gph) and a water change, the O2 dropped. Typically I leave a little below the lily pipe to add surface movement, after the CRS multiplied and the plants grew in a little, the O2 was dangerously low. Well, so low I nearly lost them all, saved the other 7 fish.
I'm so stupid.
Anyway, I'm 110% done with lily pipes.
I like current and high O2 levels.
They are terrible to clean, and adjust and ofter either .......noisy degassing grugle, or no O2.
Yes, you can adjust them, but evaporation and being able to wander away for a day or two without messing with it seems a joke. Heck of way to learn how really little O2 they add with surface movement if you add just another 1/2" or even less water.
I'm pissed, I had grown those fish up from 1/2" babies to about 1.5" over a year of pampering.
Hard lesson to learn, but everyone does, no matter how careful and good you think you might be, Murphy will get you.