You're alarmed over the wrong things here.
GH/hardness is
not really a useful reference point for saltwater the way it is in freshwater. Normal reef-strength saltwater is already
extremely hard by freshwater standards, mostly because of the calcium and magnesium content, so a general hardness strip will often just peg at max and not tell you much of value.
In reef tanks you generally want to track salinity, alkalinity, calcium, magnesium, nitrate, and phosphate separately. I’d also verify what your alkalinity number actually means. If that “80 ppm” is alkalinity as CaCO3, that is only around 4.5 dKH, which is
excessively low for a reef. If you meant
8.0 dKH, then that part is fine.
I would stop dosing Reef Code A/B unless you are testing calcium and alkalinity and seeing actual consumption and know those numbers are low - as you did not mention test results, I have to assume you are not testing. If there are no corals, clams, heavy coralline growth, etc. consuming those elements yet, dosing can just raise numbers unnecessarily above and beyond what should be good base levels from your reef salt mix (assuming you are using good salt with good quality control). Same general thought on NOPOX - nitrate around 10 ppm is not usually a problem, and carbon dosing without a clear need can cause more trouble than it solves. In fact, your nitrate is
fine for a reef tank, established or new - I wouldn't be trying too hard to drop it unless you're trying to keep something ridiculously sensitive to it, as most corals in your tank want a little free NO3 and PO4. And since you didn't mention a PO4 number, I have to assume you're not testing that either...
First thing I’d check is the RO/DI output with a TDS meter to ensure it is reading 0 TDS, then confirm salinity of your tank water with a reliable tool (speaking strictly for myself, I don't like refractometers, and prefer either a TM floating hydrometer, a Hanna checker, or other calibrated electronic probe like on an Apex or Hydros), and then re-test alkalinity with a saltwater-appropriate kit measured in
dKH,
not ppm. From there, test calcium, magnesium, nitrate, and phosphate before adding or adjusting supplements.
The only thing I see in your list I
wouldn't stop dosing right now is the Purple CX. That should be fine for now, but you really need more saltwater-appropriate testing going on here. If you're really super concerned, order an ICP-OES test that includes a vial for an RO/DI sample (the
ATI ICP-OES test does, as do some others).
Again, you need a saltwater specific Alk test that reads in dKh. If your alk is TRULY 80ppm/~4.5 dKh, then yes, you need to be dosing alk - depending on the size of your tank, and what (if any) other corals you have consuming Alk, you're very likely to be needing a lot more than 2ml/day: my 50 gallon system isn't even especially heavily stocked with corals, and with my lights up I dose as much as 20ml/day of Reef Code B.
Even if there are
no corals in your tank, 2ml/day is likely too little to make any real difference any time soon for any tank bigger than ~40 gallons - yes, you may eventually get dKh up to ~8.0 if there's nothing else actively consuming it, but you might be a loooooong while getting there, burning up reagents from testing Alk every day or two. Instead, you need to do the math on how much Reef Code B it's going to take to get your volume to ~8dKh, and then spread that out over ~2 weeks, so as to slowly bring your system into a healthy zone while not shocking anything currently living in the tank.
Get a test kit for Alk, Ca and Mag if you don't already have it (Red Sea is fine for these), and Salifert test kits for NO3, PO4, all of which you should be testing monthly or so, at least. If you don't like colorimetric titration tests, consider investing in electronic Hanna checkers for saltwater Alk (HI772), PO4 (HI774) and NO3 (HI782), since these tend to be the most commonly-tested parameters.
