I'm looking for some advice about an ongoing Phosphate issue I'm having. My levels (with a Hanna ULR tester) have been hovering around .2x for quite some time and have been much higher for short periods in the past couple of months (>.5). The 150g tank is about a year old at this point with a crushed coral bottom and some reef saver rock. I have 2 tangs, 4 clowns, a mandarin, a diamond goby and some snails & emerald crabs all of which seem happy as can be but no coral yet. I feed them a pinch of BRS pellets twice a day. All of the other tank parameters seem reasonable (Temp 80, 0 Ammonia/nitrite, pH 8, salinity 35, nitrates 5, alk 9, cal 450, mg 1450) but as expected I'm fighting a lot of algae on my rocks, even with a much shortened light schedule.
For control I've been trying a few things. First I tried GFO in a media bag in the sump with no real change. I bought an Ice Cap algae scrubber---which is producing a lot of brownish algae---but so far that hasn't affected things much. I've also been using Phosphate-E, which does work quite well in the short term, but the levels always seem to creep back in a few days and I'm concerned that I'm already on my second bottle (which seems excessive). I finally bit the bullet and just installed the BRS dual GFO/carbon reactor with the 150GPH pump (along with a third bio media reactor for nitrates) but after almost 3 weeks of that (as much GFO as it would hold) and changing the GFO every week (which I know I shouldn't need to do so soon) my levels are still way too high and not really going down. And of course I do weekly 15% water changes as well using RO water and Reef Crystals salt.
As for root causes I can only think of two possibilities. I did have an issue with my RO system for awhile so I suspect I could have introduced some phosphates a few months ago that way. I also had a Royal Gramma a month ago that "disappeared" and I suspect may have crawled into some inaccessible cavity in the reef saver rock and died but I could never locate him.
So what am I missing? My assumption was that the GFO would knock it out quickly but that hasn't proved to be the case. I've heard that Phosphate can "leach" out of rock for a long time but shouldn't the GFO be able to keep up with that? Should I keep using Phosphate-E (which does work)? Any suggestions would be appreciated!
For control I've been trying a few things. First I tried GFO in a media bag in the sump with no real change. I bought an Ice Cap algae scrubber---which is producing a lot of brownish algae---but so far that hasn't affected things much. I've also been using Phosphate-E, which does work quite well in the short term, but the levels always seem to creep back in a few days and I'm concerned that I'm already on my second bottle (which seems excessive). I finally bit the bullet and just installed the BRS dual GFO/carbon reactor with the 150GPH pump (along with a third bio media reactor for nitrates) but after almost 3 weeks of that (as much GFO as it would hold) and changing the GFO every week (which I know I shouldn't need to do so soon) my levels are still way too high and not really going down. And of course I do weekly 15% water changes as well using RO water and Reef Crystals salt.
As for root causes I can only think of two possibilities. I did have an issue with my RO system for awhile so I suspect I could have introduced some phosphates a few months ago that way. I also had a Royal Gramma a month ago that "disappeared" and I suspect may have crawled into some inaccessible cavity in the reef saver rock and died but I could never locate him.
So what am I missing? My assumption was that the GFO would knock it out quickly but that hasn't proved to be the case. I've heard that Phosphate can "leach" out of rock for a long time but shouldn't the GFO be able to keep up with that? Should I keep using Phosphate-E (which does work)? Any suggestions would be appreciated!
