What is your phosphate management routine?

[Delphinus]

Something I've always been curious of, is people's approaches to managing phosphate in the reef tank.

This is something that over the years I've taken a very casual approach to, to a very heavy monitored approach. I've used all kinds of GFO, I've used chaeto and macroalgae growout refugiums, I've used Zeovit. I ran every kind of test kit, I went out and bought a low range Phosphate colorimeter and tested tested tested.

The one inescapable conclusion I always came to though, was that I never noticed I had a phosphate problem. I could never tell when it was time to replace GFO because I could never get a nonzero reading with the test kits. The colorimeter was a joke because the specifications themselves state that there is a 0.04 plus-minus tolerance, which to me on a 0.01 precision/resolution scale, is an enormous tolerance. Not so enormous perhaps if you have measurable amounts of phosphates in your tank at 0.1 (ie., ten times the minimum resolution) but that is something I've never seen happen in my own tanks.

Bu then, no discussion of phosphate is complete without paying attention to inorganic phosphate versus organic phosphate, and which of which the test kits may (or may not) be picking up on.

So, I'm posting a poll here because I'm interested to see what everyone else does for this. Please also reply and share your thoughts about what you do and why.

Do you observe levels of PO4 or have any kind of testing routine for it?

If you run GFO, when do you replace it out? Do you observe levels and test when you notice an increase? Or do you simply follow a timed schedule, and take faith that you are replacing it frequently enough, and for that matter, take faith that it is giving you a benefit for doing so? Or have you noticed an actual difference in the tank before and after?

Or do you run Zeo, and call it done (since ULNS's will scavenge PO4 as well as NO3?)

Or do you simply run a fuge? If so, do you call it "done" ? Or do you also test your PO4 at some regular interval?

If I've missed anything in the poll options, please let me know, if I can edit it in to add an option, I will do so.