Hi
@SunnyX this is great info - thank you so much. I'm having issues with my tank with nutrients and nutrient removal. I have low nitrates and if I don't dose them, they bottom out; with dosing I keep them steadily around 5-10ppm. However, my PO4 is high and if I don't keep it in check, it will increase to 0.3-0.5 and beyond. At that level, I find that there are many SPS that I can't seem to keep healthy, but others that thrive. My tank is about 3 years old, and I have never successfully grown SPS for a long period of time (had some spurts here and there), despite ideal conditions.
Over the past year specifically, I've been in a constant battle trying to keep PO4 down; I tried both GFO and LC for a long time. GFO seemed to be too up-and-down and I couldn't find a good way to balance it smoothly. LC worked (dosed daily into a 5m sock) and kept my PO4 low, but my corals never seemed to be happy (they didn't die, but they were not growing or colorful).
I have never carbon dosed because my nitrates were never an issues. I always just focused on trying to lower and keep PO4 stable around 0.03-0.10 or so.
I then a few weeks ago tried carbon dosing as you described, and stopped the LC. At the onset, I had NO3 of 7ppm and PO4 of 0.08. I have a 165g tank and started with 2ml of NP Bacto Balance daily in the morning, along with 10ml of MicroBacter7. I have a strong skimmer (Bubble King Mini 180) which is running 24/7.
After 2 weeks, my NO3 is at 14ppm and my PO4 increased to 0.16. Also, my SPS corals started to decline in health and the tips of some of them started to die and get algae on them. I didn't change anything in my system other than stopping LC and adding the NP Bacto Balance and MicroBacter7 as noted.
Lastly - I did notice that I had a LOT more coralline algae growth, which is great. My front glass, which never gets coralline on it, has speckles of it everywhere. So it seems like something is working!
Any thoughts on what I could be doing wrong? I started with what I think is a low dose of NP Bacto Balance, and didn't change anything else. But my nutrients are increasing and my corals seem to be hurting more than ever. I have Elimi-NP as well, but haven't used it yet.
My final note would be that all of my other parameters are what reefers would consider ideal for SPS - these have been backed up with numerous ICP tests and personal testing with various test kits (I gravitate mainly to Hanna - PO4 and Nitrate are both through Hanna).
Thanks for any insight you have!
-Scott