Big problems and I don’t know what to do

[Gahamilton]

Ok so background information, I have a 60 gallon frag tank with 40 gallon sump. I have been battling low nitrates and phosphate for months. Both test are zero. And I have been doasing for both For Christmas I got a skimmer and decided to put it on the tank not thinking about it. Over the next week or 2 the corals started to look horible bad color and polyps out. I stoped the skimmer a took it out due to thinking that it was taking out the dissolved organic solids that the corals were thriving on. At the same time I removed the skimmer, I also got 3 new fish given to me, and the next big thing that happened at the same time is I spilled 2 part doasing in my tank jumping the ALK from 10 to 12.5, it has been stable at 10 for months. Now to the present time about 2 weeks later and the corals still look bad and the tissue is now receding. I have continued to doas nitrates and phosphate, now my nitrates are readable on a test kit at 2.5 a phosphate still 0. I know I messed up at several point. I have also noticed a slight haze in the tank I believe is a bacterial bloom. I don’t really know what to do now, I really just need some guidance. This is the first day I have seen tissue receding on the candy canes. Ask any questions and for clarification on anything I just really need guidance. Also a note Greene cyano bacteria showed up when k had the skimmer on. Now that it is off it has mostly gone away. This all started when I put the skimmer in. I also started doasing trace elements at that time. Just trying to give all information so someone might notice or think of something. The montipora digita is supposed to be green and the one in the back is supposed to be red

 

[Gahamilton]

Should I maybe just back to exactly what was working fine before instead of trying to fix the mistakes and get to non zero numbers