I pretty much stopped chasing nitrates because no matter what they tend to run high even with skimmer, ozone, bio pellet reactor, sandbed and refugium (restarted and pretty new). Here lately been doing 40g changes every couple weeks to get it back into the realm of reason as part of a remodel. Phosphates pretty much the same but when they get a bit much, I run GFO. Of course, I run a mixed reef with lots of fish, LPS and softies these days with not much in the way of SPS anymore. I suspect most of those issues are all part of old tank syndrome (almost 10 years). I actually just checked nitrates (Hanna) and up to 45ppm and doing another water change this weekend anyway. In reality now that I have a second tank going, I need to move all the sand bed inhabitants to the new tank and do some serious sandbed cleaning even if I do lose some pods, mini stars and worms. Interesting thing is I have not had any algae issues in years or problems with fish and corals.