What is preffered testing for these parameters and what should they be in a sps environment
Off topic my sps grow but grow very thick why is this happening
I personally like my Hanna alkalinity checker (or salifert carbonate hardness, it's easy to read), salifert for Nitrate, and I use the Hanna ULR phosphorus meter to measure PO4.
The levels and what they need to be is likely to be the next hottly debated topic if the the Nutrients vs. no nutrients topic ever ceases.
I personally chose an arbitrary number of 2.5ppm of NO3 to try and maintain, and try to keep my PO4 between (.02-.05ppm). Some people keep their NO3 at 5ppm, some higher, some only keep a trace of NO3. The most important part is that there needs to be some of both, not some of one and not the other (imbalanced nutrients) or no detectable nutrients. I arbitrarily chose 2.5ppm because it was easy to tell from 1ppm and 5ppm in the salifert test color range. That was my reasoning.
Your nutrient level requirements are closely tied with your alkalinity levels, and your lighting intensity. As your lighting intensity increases nutrients become much more important, high light environments require the most nutrients to prevent bleaching/permanent damage from phosphate deficiency.
I don't run high alk, but if you do, you have to have the nutrients in place to support the environment.
Our little glass boxes contain an extremely dynamic environment, there really aren't any perfect guidelines from one to the next.
Maybe someone with some more experience can come along and suggest why your SPS grow very thick and dense. I'm not entirely sure that is a bad thing. I would think dense growth (as opposed to long lanky growth) would likely suggest that you are providing enough intense as well as dispersed light to support dense growth. I'm sure circulation play as equally an important part in their growth patterns and density.