I've been reading through your thread and I kept a nano tank for six years with both sps and LPS. My tank was twice your size, 28g nanocube. I also ran two kessils. Nanos are such a challenge. My observation over time was the difficulty arose from keeping parameters stable and consistent. I'd go through swings all the time and the more parameters swung up or down, the more problems I'd encounter. When things finally changed for me was when I simplified things. So, in reading through I see your doing large water changes once a week. My opinion is that's to much. I did the same thing and got similar results. Your Alk is a different number every time, 8 then 7.8 then 7.4. That's a lot on a low water volume where parameters shift quickly compared to a larger volume of water. When I switched to 10-20% every 4-5 days things stabilized much better. My goal was to change 100% water every month and never go more then 5 days without a wc. My parameters stayed consistent. I also used to use Red Sea salt and found parameters of salt could change from bag to bag or bucket to bucket. I switched to IO and things improved for me in regards to stable parameters. I've since switched to Fritz salt and really like the consistent parameters I get with it and it's the target numbers out of the box that I'm shooting for. If you increase the frequency of the wc and lower the volume the parameters should stay pretty stable with no extra help from you. I als removed the skimmer. I saw in post one you had one but never saw if you were using it. I found using the skimmer netted me nothing more then a light tea color anyway and the water changes kept the water clean and not pulling out the little bit of organic waste that the skimmer pulled out helped my nitrates. I supplemented a little Acropower. So the moral of my story is that I think the stability is the key and the success lies in the water changes. Good luck on getting it back. It's been a good build so far
