To dose or not to dose?!?

[TheReefDiary]

Okay so my tank has had coral in it for almost a week. In that time my alkalinity has dropped substantially. Was 8.4 now it's down to 7.7.

I've been doing weekly 10% water changes, but haven't tracked alkalinity yet after water changes + corals. However, I feel that's that a large drop in 5 days.

My current parameters are:
PH 8.2
Alk 7.7
Nitrate - 15-20 (both api and salifert)
PO4 - 0 - .10ppm (api - obviously can't Guage minute differences with API, but can tell its in that range, most likely closer to .1)
Ca - 420 (was 450 before)

So should I go another couple weeks and see if my alk keeps dropping quickly then based of those results dose the days it drops?

Should I just run with the naturally lower alk? But won't this hurt my growth rate/healthiness of the corals?

Also still unsure about my light settings but it seems that with alk going down corals are happy. Surprising because I have it 10% white 20% blue at peak.

 

[Spare time]

When your water change schedule no longer works to keep numbers correct like alk, then dose.


PS get a new phosphate test. The API test is useless for phosphate.