ARM Media and Phosphates


Premium Member
I was just curious what other people's experience with this media is? I just changed my calcium reactor and didn't need it online right away, so instead of taking the media and soaking it in RO/DI for a couple of weeks, I put it in the calcium reactor and ran the reactor on a little closed loop through a 5 gallon bucket. Now, I wasn't injecting CO2 into the reactor, so the media wasn't breaking down, but it's not breaking down when it's just soaking in RO/DI either. So, I figured this should have still been sufficient to help leach any phosphates. Anyway, I ran it like this for a full week, and tested the water several times, and phosphates were always undetectable on Salifert test kit! I was pleasantly surprised. This was the ARM Extra Coarse media.

So, any other experience with the media in general? Or thoughts on using this method to test media for phosphates?


New member
There's a tiny amount of phosphate in any media that's based on coral skeleton and shells, but it's so small that it's nothing to worry about.

Randy went over this in the chemistry forum, the amount your reactor will add with ARM is insignificant compared to what you get from your typical feeding followed by fish poo.