Help with getting parameters

[BaileyAR]

Im having trouble getting my parameters back in place, not that they were perfect before but corals were growing now they are reversing.
My test previously on a steady basis was
35ppt salinity
~400 cal
10 dkh
0-5 phos
0-5 nitrate

Once I noticed corals dying I tested with
37ppt salinity
320 cal
5 dkh
0 phos
0 nitrate
I also then tested ph and was at about 7.

Over the span of a week I’ve slowly tried to correct the numbers. I did a water change. Trying to feed more for phos and nitrate. I dosed with Seachem reef buffer to raise ph and alk. After 2g doses for 4 days 1 dose a day and testing each day. Ive gotten to
35ppt salinity
320 cal
8dkh
8 ph

So my question is what happened? I do have a good amount of corals. I want to see them growing again. Ive gotten good at keeping my salinity in check, I have a ato and check frequently. I did wc weekly for the first 4-5 months of the 6 month tank untill i start bi weekly. But after all this ive gone back to weekly again.

 

[Bucs20fan]

phos and nitrate are your issue. Yes 5 dkh is really low, which is why your ph dropped. Corals require phosphate and nitrate to feed. Having Double 0's on those two will kill corals. You should always have at a minimum detectable levels of both.

 

[TokenReefer]

Yeah, your nutrients bottomed out is a probably simple way to put it. Your alk is very low and you have no phos or nitrates for the corals to consume. Alk has a strong affect on coral growth. What happened? Your corals grew and consumed alk and N+P Just gotta keep those numbers up if you want to see them growing again as you mention

Also 37 ppt is not gonna kill anything but it affects ratios of all other components in the water; I'd suggest sticking to 35 ppt for stability so that your testing and, well, everything is consistent