No doubt in my mind, worth every penny.
I have been using the phosphate and alkalinity tests for a couple years now and they are perfect! Easy to use and very very accurate.
I had the calcium one but found it to be too complicated and not accurate at all. I ended up returning it to BRS. I believe you have to use distilled water and not ro
water, at least thats what Hanna instruments rep told me when I emailed them about the inaccuracy I had.