This is a good question for us beginners who want to keep corals . Mr Randy's graph is a great reference but kinda broad 7 to 11 dkh.
There are so many differing OP's on where in between is best . Then the "Keep it stable " part comes in . All the differing Ops makes it tough for a newcomer to decide what number to pick then strive to keep it stable.
I usually go with alk my new water mixes to. but even that changes from batch to batch.
So what is a good all around number to shoot for so we can work on the stability end of it ?
I try to keep it as close to 8.5 as possible.
It just depends on what you are planning on keeping and your methods on nutrient export.
Bottom line is stability.....