my statement on removing/adding the spheres was to express the extreme case on how much they do not matter in reef systems, they provide zero help/they don't harm anything when removed just the same.
They would be a critical, crucial element of surface area in a system that had no rocks or sand, though (since no reef tanks are set up that way, these spheres aren't needed in reefing, they're needed in heavy fish stocked freshwater setups/those are low surface area aquariums)
they could be very helpful and crucial in quarantine setups (no rock stacks in the center water)
Our minds simply cannot envision a system in which a portion of a biofilter is removed in a reef display, let's say in this case it represents 3% of your total active biofilter surface area to remove those spheres, and the overall cycling ability of the aquarium doesn't drop to 97%
it does not work that way in biosystems that employ as much live rock as we do right in the middle of the display circulating wastewater. pods hide there, nitrification of ammonia occurs on surfaces and by plant uptake there/the spheres are the same dynamics of anyone on this site hooking up 7 canister filters to their already-running reef tank.
after 6 mos, those 7 canister filters are absolutely linked into, and sharing bacteria and waste control with the whole system. they are what the old school cyclers would call bound into the system, crucial bacteria they carry, like those spheres in your tank.
but you can go right in and remove all 7 canister filters immediately, without ramp up, and on any calibrated seneye (or that fine hanna meter above) your ammonia control will NOT change it will stay the same as it was before you added the 7 canisters, and the very hour after you removed them (subject to small daily changes but never hitting and sustaining toxic levels-this is how reefs run before the extra canisters were hooked up)
a rock stack will control ammonia into the thousands ppm nh3 for 99% of reefers and for the other 1% on micro stacked nano reefs, tenths ppm is the most you'll ever see as nh3 form, going off all seneye patterns and so far all these hanna checkers too.
7 canister filters are neutral impact to any reef tank on this board, and marine pure biospheres are the very same. were it not for these big rock stacks we all keep, we'd need all that freshwater surface area help.
any reef on this entire board can remove its canister or hang on filter immediately from the display, and nothing will change about their cycle when using seneye meters, we've been testing that for years now in the sand rinse thread. I can yank someone's entire sandbed on seneye or mindstream (another digital device from 6~ years ago) and the conversion rates stay the same.
we are free to add and remove surface area at all in reefing due to the power of the rock stacks we all copy from one another in scale, in all reef setups small to large. We even go so far as to remove people's sand + half their active rock stack, to make more open scapes, and even that doesn't change filtration ability in the tank. Even our rock stacks are orders beyond what's needed to control a common reef tank bioload in terms of nh3 management.
This is the #1 reason why in four threads right now bumped in the chem forum you can see me vehemently disagreeing with anyone who says a 9 month old reef tank somehow lost it's ability to control ammonia/nh3