400 gallon project

[untamed]

I have been wrong once before...but this time I really think the aquarium has turned around.

As most everyone knows, the past year has been a steady downward decline in the health of the coral. I lost so much coral, I can't even begin to describe it.

However, for the past 2 weeks there has been a dramatic reversal in the tank. Unfortunately, I can't say with certainty WHAT caused the reversal....but coral is growing like mad and colours are returning. Coral that had been reduced to a small puddle is suddenly shooting up branches.

1) The new skimmer went in 3 weeks ago. Could be that.
2) I began feeding ozone to the skimmer off/on. Could be that.
3) I began dosing VSV (Vodka, Sugar, Vinegar) at 4ml/day. I never measured nitrate higher than 10ppm, but since dosing began my nitrate is down to 1ppm. (almost unmeasurable) Phosphate levels have also dropped...but from a high of 8ppm to 1ppm.
4) I vaccuumed the sand bed (but I had done that 50x before) For whatever reason, this time the cyano didn't come back (VSV?)

Some things that I have NOT changed:
1) Same Salt
2) Same water change schedule
3) Same fish feeding amounts/schedule
4) Same lighting
5) Same water movement