I was browsing around today, visiting from another site, and I just couldn't let this thread go without registering and posting some comments.
There are signs of future problems already present in this tank, and it is very visible just from looking at the picture you posted. I think this is the jmeader was attempting to communicate when he suggested that it is easy to get in over your head on a reef system of this size. When you've been in this hobby for a long time, like any other activity, you develop an instinct. You start to see things differently and know when to make adjustments.
That being said, let me tell you what scares me about your setup. Hopefully this will amount to nothing and you will have amazing success. At worst you will have some additional advise to consider.
First, your reef structure is not designed well at all. You have huge rocks lying flat on the bottom, across the sand, with only 1 power head for circulation. This is a recipe for slowly cooking a disaster in any reef, especially a mini reef. Detritus accumulation is a serious potential issue, and I think you would be very well advised to take two actions. First, rearrange the live rock structure to raise these large flat rocks off the sand bed. This will allow water to better circulate beneath the rocks. Second, add the 2nd power head that was long ago recommended.
The next thing I notice is a lack of coraline algae covering your live rock. Your tank has been set up for 2 months and you have virtually zero coraline growth. You have had plenty of time to achieve significant coraline growth, and would have achieved this growth if the system were properly matured. This is an idea of how your rock should look:
Over time, something will grow on your rock. If it is not coraline, it will probably be cynobacteria or hair algae, or both. The likely reason you are not getting good coraline growth is due to calcium and alkalinity. You need to be testing for both and adding a supplement to achieve the desired range. The water changes do not appear to be doing the trick, so supplementation is probably necessary. You want alkalinity at 8 to 12 DKH and calcium at 400 - 460ppm. I personally use Kent Marine Super Buffer DKH and Kent Marine liquid calcium in my reef and FOWLR tank (pictured above). The b-Ionic product is also a very popular balanced additive. Regardless of the specific product, this is becoming a necessary part of your routine.
I also notice that you dosed strontium, molybendium, and iodine. Why? Did you test for these and find that you are lacking? It is extremely dangerous to add anything to a marine aquarium that you can not test for to confirm the existing levels. There is simply no reason to be dosing for any of these, especially given that you are presumably doing weekly water changes.
That is about all I have. I just hated to see this system, which appears to be successful, begin to experience a cyno bloom and then crash suddenly when action can be taken today.
I am a Mod on another site, so I probably won't be here to follow up on these comments. I'm sitting at home bored off my rocker today and thought I'd check this forum out. In any case, I hope you take my comments with a degree of urgency.
Good luck with the tank!