[Myka]

Originally Posted by LeanneP

I have a Remora Aqua C skimmer that is about 6 months old. Fish are sailfin tang, rabbit fish, 3 damsels, 2 clowns and a lawn mower Benny.

Hmm, the Sailfin Tang and the Rabbitfish were not good fish choices for a tank your size. The Tang will grow to a good 16+" (and quite quickly too) and the Rabbitfish depending on which species will be 8-16" which is also too large for an 86-gallon aquarium imo. Both the Tang and the Rabbitfish are also eating and pooping machines which really adds to the biological load.

The Remora skimmer is a decent entry-level skimmer, and is definitely helping to filter the water for you. Albeit a higher quality skimmer would definitely help with both nitrate and phosphate by removing organics before they have time to break down. By no means am I saying you need to upgrade, (the skimmer is just fine) I'm just trying to help you understand how things work.

If you haven't read the link Dan provided to the Advanced Aquarist article on phosphate sources you really should. Here it is again... http://www.advancedaquarist.com/2012/3/chemistry

I have just retested my nitrate with two kits and they both say 0 for nitrate but they are API and I know they are quite inaccurate. I have a Nutrfin test kit for phosphate, again it is saying 1.0. I know I need to invest in some better test kits. We don't have any stores that sell decent ones here so it is on my list for my next trip to Vancouver.
I know that I am having these issues because of the water quality so I hopeful now I have R/O water things will get back on track. I do have a TDS meter so I check all my water to make sure it is at 0 before I put it in the tank.
Thanks for all the help. I will try and find some better GFO tomorrow.
Leanne

I would trust the API test kits much more than the Nutrafin test kits. I actually use the API Nitrate Kit on my fish-only tanks. I don't think it is accurate enough for reef tanks simply because it isn't sensitive enough in the lower end of the scale in my experience. The difference between 1 ppm and 5 ppm could solve some of our problems. I think Salifert or Elos for nitrate would be a better option for a reef tank.

The Nutrafin kit I would not trust at all. Salifert, Elos, and Hanna all put out good quality phosphate kits.

Both nitrate and phosphate are just as important to a healthy reef tank as calcium, alkalinity, and magnesium so I would suggest you start there.

I did add some GFO earlier today and my hammer coral is already looking a bit better. I used Fluval brand which I am sure is not that great but it is what I had. I used the most minimum amount that they suggested to avoid bleaching.

The Fluval GFO is just fine to use. It ends up being pricier than some other brands simply because its effectiveness less - you have to use more to do the same thing. You did a good job by just adding a very small amount at first.