Nitrates and Phosphates (Suddenly) Dropped to 0

situationlol · Nov 26, 2022

I have a 6 month old 120 gallon tank (first foray into reefing). After getting cocky and throwing some sps into the tank (they died), I realized I needed to start regularly testing, which I began doing in late September. I haven't been doing it as routinely as I should, but I've tested 8 times since then. Nitrates and phosphates have always been high with nitrates coming in between 40 and 60 and phosphates coming in between 0.25 and 0.5. Before today (11/26), my previous test was on 11/8. To my surprise, I'm suddenly getting 0 for both. I thought I must have made a mistake, but I tested nitrates 3 times and phosphates twice and 0 every time. I've been using salifert. What's the deal here? Is this something over which to be concerned? I googled around and searched the forum but I can't seem to find anyone with a similar question.

As far as I can tell there have been 3 changes in the previous month. (1) I added about 7 new lps corals (they appear to be thriving) and (2) flukes made their way into my tank and I've had to do a number of rounds of prazi. Because of that I've been doing weekly water changes (~30%) instead of my usual 2 week water change. Doesn't seem like I'm taking out enough water to change these parameters so drastically. And (3) I started dosing red sea AB+. I've just been dosing half the recommended dosage.

Thanks all.

Edit to add my other parameters in the event it's relevant:
alk: 11 (higher than usual today. typically between 8-10)
mg: 1080 (also higher than usual today. typically around 1020)
ca: 395 (consistent with prior testing)

damsels are not mean · Nov 26, 2022

Probably testing error. Try a different test as reference or take it to a LFS.

Is it something to be concerned over? I am sure lots will say yes but I have yet to see any compelling reasons to believe high nitrates and phosphates really matter. Can't hurt to keep them within comfortable ranges though.