My 2 cents: skimmers are not necessary especially if fish load is light. (If you ask someone who sells skimmers - yeah they are very necessary)
Are skimmers really that necessary on all reef tanks?
I personally don’t think they are. I never run skimmers and I can keep any type of coral you can imagine, to include SPS corals.
I think that as long as you have a strong enough and diverse biological filtration (bacteria) your reef tank is set! I always stress it is key to a successful reef tank.
what are your thoughts on this matter of if skimmers are an absolute necessity or not?
Not an absolute necessity but it's hard to ignore the long history of success using protein skimmers. People have also had success without skimmers but there are alot of reefers who swear by them. The simple answer is that it's not "required" but skimmers are a proven tool that has helped many reefers achieve good results.
That said, I must admit to being something of a "skimmer skeptic" as well. I think the primary reason for this is that I don't understand how we know if what the skimmer takes out is actually "bad". Of course I expect the skimmer removes *ahem* protein... but what type of proteins exactly, and why do I want to remove them in particular?
I cringe every time someone states that the skimmer *MUST* be doing something helpful because the stuff it removes is gross/unappetizing. You are human, not a coral.
I'm not tempted to consume any of the stuff I put in my reef tank. When I used to run a skimmer I was actually struck by how similar my skimmate appeared and smelled to particulate foods (like reef roids mixed with water) that I was dumping right back into the tank. Of course I assumed that the skimmate was waste, while the filter food was food... But not really knowing what's in my skimmate, I'm just not certain.
Is a skimmer removing waste or food? I've been told by many reefkeepers that corals don't need to be fed directly, they eat fish waste. So then, why do we need a skimmer again? Maybe a skimmer is helpful in cases where you have a much higher fish load than the coral/filter feeders can keep up with, but it seems to me that in cases where there's alot of coral or filter feeders, a skimmer may just compete with the livestock for food.
Right now I do not run a skimmer, because I'm struggling to maintain any nitrate reading and I don't think a skimmer will help with the problem. I do have excess phosphate, so if a skimmer removed more phosphorus than nitrogenous waste I would be interested (someone please let me know if this is the case). I expect a skimmer would depress both and if nitrate decreases any more I'm gonna starve my coral. There are other tools I can use to address the imbalance in export like lanthanum chloride or gfo.
Bottom line imho- There are multiple tools in the hobby now to address export and skimmers are just another tool. There are also filter socks/rollers, chaeto/macroalgae refugiums, algae reactors, carbon dosing, gfo, lanthanum chloride, gac? ... and many more.
There are multiple ways to achieve a balance that will lead to good results.
