So I have some thoughts on the use of GFO and the gradual entrance into Zeovit... There are quite a few reefers that have chosen to use GFO as a form of phosphate control. Granular Ferric Oxide is an excellent way to manage phosphate levels. Combined with bio pellets and GAC, you can maintain a ULNS easily. GFO is such an effective method of phosphate control that it is often inadvertently used to mask underlying issues that have a huge influence on phosphate levels in the reef aquarium. What I have noticed is when there is an underlying issue that is the cause of high phosphate levels, stopping the use of GFO (or any other form of phosphate reduction) causes a massive SPIKE in phosphate levels. The Zeo is not able to handle this with a gradual increase in media. When you ramp up zeo levels to quickly combat the increasing phosphate levels, you risk RIPPING other essential elements from your water to quickly. This is also where the transition to zeo become very tricky. Not only are you trying to transition to zeo, but now you have to find out what is feeding your high nutrient load. Zeovit is the most advance approach to keeping a colorful SPS population. Before taking the plunge into zeo, it is best for you to understand what your phosphate will do without the use of GFO. You eventually will need to take the GFO offline. Using the zeo as an aggressive means of phosphate control will most likely lead to very bad things.
The reefers that I am working with are learning how to use zeo with their system. We are also finding what contributes to phosphate and how much of a contributor each factor is. It's been a bit of a challenge, but we are getting there. With my tank, I can use very little zeo media and have great results. The other tanks that have higher fish loads and more feeding requires more media. I'm finding that at 60% of the recommended zeo amount, things start to stabilize. I now have 60% of the recommended media in my own reactor and it is the most media I will use on my tank. More than 900ml in my reactor will lead to pale coloration and weak corals. In the other tanks I am working with, 60% is just the start. Further down the road, a lesser amount of media can be used in these other tanks. The issue with using the total amount of zeo immediately is the reason why I recommended the gradual increase in the first place. A sudden transition to zeo can lead to rtn, pale colors, as well as other issues. I am dedicated to helping my group of reefers transition to the full zeo method. I will continue to update everyone with the progress.
Final thought"¦ Every tank is different. Every tank uses different forms of nutrient management. Some methods will make the transition a little tougher, but it still can be done. Hope everyone finds this information useful.
Calvin "“ Haven't forgotten about your question. I'll get back to you tomorrow evening when I'm back to answering questions again.
Warmest Regards,
James