I never dosed, but I also never tested for it.
Lots of good info here....
Aquarium Chemistry: Strontium and the Reef Aquarium — Advanced Aquarist | Aquarist Magazine and Blog
"That 15 ppm
strontium matches my measured value for the Instant Ocean salt mix that I use."
[I also use IO so I expect my strontium levels are similar. Sr levels in natural seawater are 8ppm (Reef Aquarium Water Parameters by Randy Holmes-Farley - Reefkeeping.com).]
"My recommendation is to maintain strontium in reef aquaria at something approaching natural levels. There is no evidence that strontium at these levels in detrimental to any marine organism (although it might be). There is strong scientific evidence that some organisms need strontium, albeit not the organisms that most reef keepers maintain. Finally, there is anecdotal evidence from a number of advanced aquarists that depleted strontium is detrimental to the growth of corals that many aquarists maintain.
How is one to maintain natural levels? That, of course, necessitates a suitable test for strontium. Perhaps the test kits are suitable for this purpose. If not, sending a sample out to a lab might be a reasonable alternative for some aquarists. If the result comes back in the 6-15 ppm
range, there is not likely any action that needs to be taken. If the level is higher than 15 ppm
, reducing the strontium levels via water changes with a suitable salt mix may be the best method. If strontium levels are below 6 ppm
, adding a strontium supplement may be in order.
Remember: in my aquarium without any recent strontium additions, strontium was already elevated above natural levels. I would not like to see it get any higher. Consequently, adding a supplement in the absence of knowing the strontium levels is not advisable."