Further to this the tank took a turn for the worse and went into a 4-5 month cycle of Algae and then Cyano which heavy water changes and the usual fixes didn't even affect.
After that the hair algae resolved on its own. Leaching was not the suspected scenario at this stage as tank was at the 2 years mark.
I followed with a Zeo protocol (Zeobac, Coral Snow, Zeozyme and zeostart 3) which took care of the cyano but was too expensive to maintain on the large volume so stopped it 4 months later and cyano came back with a vengeance. At that stage any SPS I would add would look dry starting day 3-4 and turn into a skeleton without tissue sloughing or STN RTN. Softies and LPS were doing fine.
After that around a year ago I accidently discovered while cross testing with a friend that my Po4 was at at 0.9. Verified it in a lab test and it matched. So I switched to Hana from Salifert since then. I had previously tested with many PO4 testkits and for some reason they were only giving me a perfect 0 and my nitrate was on the rise up to 10-15 which tricked me into thinking PO4 was limiting nitrate reduction so I stopped the PO4 reactor making things worse. So several KGs of PO4 and hundreds of gallons changed and I got the PO4 down to where it should be. This resulted in immediate disappearance of the Cyano and a couple of frags that I thought dead coming back to life!.
The Irony was 3-4 tiny frags (couple of polyps each) made it through all the dilemma while I was burning my SPS collection and any new addition.
I normally thought that was the end of the ordeal and started adding corals only to have the same outcome even with controlled PO4 at 0.03-0.05. At this time I got in touch with several LFS and people that maintain tanks worldwide and also luckily was introduced to a team of specialists that were visiting a public display with a 10 m long Coral reef tank that was struggling with similar issues.
We went through a huge list of things: Chloramine, PH spikes or dips, O2 levels, contaminants, Pesticides, switched chillers in a row to make sure my 2 chillers were not leaching anything, change of salt, change of my RO unit and additional filters (1 Micron carbon, and 0.09 sediment) with frequent replacement, checking tank, frags and sumps with a magnet to make sure no metallic things have dropped there, air purifier in filtration room, lights change, slow acclimation process, leaving tank with no corals for weeks to make sure there was no pests and dipping corals randomly to make sure they were clean, adding established corals to avoid stressed ones. Corals were doing fine in the Quarantine tank but would dry off few days in DT.
No matter what I did Result was the same with any new addition and to make things worst the tiny remaining frags were still there completely brown.
At this stage the only logical next step was to restart the tank which wasn't an option as I wasn't going to go through another cycle with no warranty that whatever was wrong will happen again after a restart.
Went on for few more months with a regular maintenance method and not making any changes to address anything and few weeks back I started seeing colors on the survivor frags and a couple more I thought dead came back to life and since then the tank has looked better every day with growth and colors sign.
Since then I have started adding corals in batches and luckily things look good, Pics to come
