I have been very aggressive with phosphate control ever since I started my tank. Recently my SPS growth has slowed but more alarmingly the color has faded badly. I have had problems with nitrates rising since finishing my fish stocking. I attributed the color and growth problems to the nitrates but Randy Holmes Farley suggested that low PO4 could have been the problem. My phosphates have been undetctable for months. I started carbon dosing about two weeks ago and in accordance to recommendations of RHF shut off my GFO reactor about the same time. My nitrates have yet to budge but my corals have bounced back very well. Colors are better than they have been in my memory. I firmly believe the PO4 is responsible. Understand I'm not saying you don't need to control phosphate. It's well proven that you do, however zero phosphates will limit growth as it's a vital part of the skeletal structure of hard corals. Currently my phosphate is still low at 0.006. I'm going to let it rise to about 0.02-0.04 and then try to keep it just below that. Carbon dosing will reduce phosphate some but it is much more effective in lowering nitrates. I will have to run GFO but not as aggressively as I have been. Just wanted to share this and hope some of you fellow SPS keepers will share your experience. This experiment is young but after a lot of reading I believe it's on target. What say ye?
Phosphate is a double edged sword, too much and we have inhibited calcification and the arrival of nuisance algae, conversely too little and limited overall biochemical stability. ATP is a pretty important molecule for life. Also low pH can inhibit calcification as well. At this present time I am in search of some soda lime to battle my low pH problem. Soda lime is a mix of Calcium hydroxide, water , NaOH and potassium hydroxide. The soda lime media will eradicate my low pH problem by absorbing CO2. I am new to carbon dosing, need to read up on the subject
I have suspected the low PH/ coral growth problem for a while I just never bothered verifying it. I always suspected my water was too clean because I could only keep Xenia alive for about 2-3 weeks. I had no problem keeping a clam alive or my dinner plate size Sebae but I couldn't keep any "easy" coral alive for more than a few months. I always kept my levels right around 0 and if they increased I did a water change. With all that said, and before I get flamed, I used tap water. In 10 years of doing this I have never used anything other than tap water until now. These two tanks that I have set up right now I am using RODI water and the only thing I check is my salinity/specific gravity.
