This past Wednesday, I had the pleasure of feasting my eyes on the Wardlaw 120. Wardlaw has a great setup in the front room that's perfect for saltwater reef tank oogling.
He ran me through the history of the tank and what may have led to the tank crash. We believe to have pinpointed it down to an overdose of alk in his ATO causing alk levels to skyrocket in his tank. Both of our hanna meters topped out at 300 ppm (16.8 dKh). Wow!
Here's the suite of tests I ran on his water and the results:
Salinity - 1.024 (Milwaukee Digital Refractometer)
Alk - >16.8 dKh (Hanna Meter)
Ca - 120 ppm (Red Sea)
Mg - 1,120 ppm (Red Sea)
PO4 - 0.04 ppm (Hanna ultra low phosphorus meter)
NO3 - >64 ppm (Red Sea)
Basically, the alk overdose wiped out a majority of his corals. Luckily the fish survived and a couple of zoas. The calcium most likely precipitated out and ended at a super low concentration of 120 ppm. He continued to run GFO the entire time so his phosphate levels stayed pretty reasonable but nitrates have shot up significantly with the coral die off.
We also took a look at his RO/DI system and all of his filters and DI cartridge needed to be replaced. It was probably not there yet but would have started to add nutrients into the tank if it didn't get replaced soon.
So the strategy we discussed was to do some large volume water changes to get his alk back down and his calcium more in line. He's ordered some new filters for the RO/DI and they are on their way but the more pressing issue is the super low Ca and the super high alk, so in this scenario, not waiting for the new filters and doing the water changes now seems more logical.
Once levels are closer to NSW levels, we can probably use 2-part to tweak the levels just right. Wardlaw has mentioned he is more interested in setting up the system for the long-term and plans to get a CaRX to supplement his foundation elements. For nutrients, he already has the GFO online and we haven't discussed how to maintain nitrate levels <5ppm just yet.