Yes.....but I don't really get hung up in the initial levels due to the larger tank and the amount that I am changing out. its just as easy for me to add in another half cup to through it off a couple of points.....
While were on the subject:
Water changes I am beginning to believe are a chaotic are potenially dangerous thing that may not be needed at all with dosing these days.......why change the water if you have chaeto or are sugar/vodka dosing to get rid of nitrates, and are dosing 2 part to keep the alk/ca and traces up?......why change the water????? It just upsets the balance....however small, it does one has to admit......messing with the SPS I am all about consistnecy these days.
I digress:
After water changes I readjust my dosing due to any inconsistencies that may occur and tend to test more after a large water change.
However, I could see this becoming an issue with someone using only water changes to maintain their levels.......
This is probably the prime reason I am hesitant to mix my own two part per Randys recipe just to save money.....I don't trust myself to make consitent batches everytime.
The times I have tested it, all levels have been within spec......but aren't the "same" all the time....I think if we demanded that, the cost of salt would double for them to ensure that quality......thats why ReefCrystals I think is more spendy as it is compared to others.....but I like it and used 1 bag of IO the last time, but switched back with the last one......saw little difference because I already dose to compensate for any deviation.....call it piece of mind spending the extra on RC, might as well spulge on the corals a little ehh?......if I find a salt that will grow SPS 10 inches a month....Ill change, but I think what I have is working for now......I would like to reread that salt study again though to see if there have been any more findings......