Hey Ty! Glad to see you're a night owl just as I am.
What a GREAT post! Thank you for sharing your experiences with this method. I'm going to (attempt) to elaborate on my thoughts on the matter, and hopefully make sense of everything I've read including your thoughts. PLEASE PLEASE correct me if I'm wrong anywhere - it most certainly wouldn't be the first time . I can use my 2+ year hiatus as an excuse!
There is definitely a lot of reading to do on the subject. I agree that those with algae issues definitely need to assess their specific needs before using this method. Those afflicted with the algal curse like GHA, or worse, cyano, may have higher PO4 and lower NO3. Luckily cyano can be treated (in most cases) by Chemiclean, unlike GHA which is treated well and effectively with nutrient balance and/or manual removal (I always liked my Lawnmower Blenny ).
But what of those who consistently get readings of 0ppm NO3 & PO4, don't suffer the headache of a buildup of algae/cyno, but DO struggle to keep more difficult corals such as SPS alive? With a lighter bioload and little to no excess nutrients, dosing might be a viable solution. Or, reducing their exportation of excess nutrients and increasing their bioload to achieve these results organically. It all varies based on what your specific tank needs are. If I have a heavy bioload, and an lite-moderate method of eliminating excess nutrients, this theory would DEFINITELY not be a good fit for my needs. Perhaps carbon dosing would prove to be more effective if this was my case.
I remember years ago, when I first started diving into the wonderful world of Reef Keeping, hitting that 0ppm mark was AWESOME! After a while, I stopped checking my PO4 and NO3 levels, as I never tested above 0ppm. I also HATED water changes... and still do... so I stopped performing them regularly. Then, I began to notice excellent growth and great PE (mainly in that Sunset Milli colony... I miss that thing). I tested my water and saw the NO3 levels were around 2-3ppm. I inevitably accepted that I wouldn't be able to get them lower due to my increased bioload in a 34g Solana. Heck, the fact that I had a Fuzzy Dwarf Lion who loved ghost shrimp and being hand-fed (my mother really loved that trick) could alone build up NO3 REALLLLY quick. It really wasn't until I began reading these articles and posts that I remembered the "eureka," moment I had so long ago.
Now, I can't say with a great deal of certainty that was the only contributing factor, but perhaps it did play an integral part in the success of my tank.
I'm super glad to hear that you did find success in making your corals happy with this method, even if done while fallow. That shows that the theory behind this methodology is correct! I understand with the reintroduction of fish might eliminate the need to resort to this method again. Especially if you're a heavy feeder. But, what if your nutrient exportation IS so heavy that you begin to get into a dangerously low level of nutrients? Would you begin dosing again, or lean towards something else?
Thanks again for engaging! Hopefully this thread helps some of our members!