RowaPhos Phosphate Removal Media
 

Can anyone tell me how offen do you change phosphate removal media? and also what is good test kit for that? I am running reactor for couple month and I just realize when should I change. Thanks

If you have a SPS tank you should buy a high sensitivity test kit like the D-D Merck kit (~$80), if you don't have a SPS dominated tank then a Salifert or Elos kit will do. If you have a SPS tank you should change the media when it creeps above 0.08 ppm. If using Salifert or Elos then the media should be changed when it shows up on the kit even as a trace.

When to change the media is a bit of a trial as there is no set time. It depends how much media you have used in relation to the volume of water, how much phosphate is already in that volume of water, how much phosphate is being added to that volume of water daily, and how much phosphate is being leached into that volume of water. Test kits and visuals are your best bet. If you see an increase in film algae it is time to change the media. Keep track how long you go between, how much you use, and what brand so you can set yourself a rough schedule.

I don't use GFO anymore. Bio pellets, vodka and sugar dosing (Yes I use pellets and vodka) works for me. I keep my phosphate level 0.02-0.06 ppm and nitrate level not detectable by the test kit.
IMO a phosphate meter is a very good investment.

I'm assuming you're using the Hanna phosphate meter? How do you like it? Have you compared results to any test kits? It was all a big deal when these came out, but now I don't hear anything about them.

Yes I did. They work and they take the guess part out. You still have to buy reagents, wich are comparable as price with medium to high end test kits. You have to clean the heck out of the test cuvette, even soak them in hydrochloric acid time to time, but the big advantage is the use of an electronic eye. IMO it is worth to use one.

If you test the water coming out of the GFO reactor and compare it to the tank water you get a pretty good idea when it is time to change the medium. I have a Hanna meter also, I love it now to get a nitrate meter.