BRS GFO
 

So my phosphate spike to .11 with hanah test and i bought some GFO pellets from bRS. Base on my tank volume, I need 2.77 cups. I don't know why it is too much as only see ppl with large tank only run about 1 cup.

Should i do 2.77 cups?

Thanks

Well... How much you need is dependent on how much overall phos you have and how quickly you want to reduce it. The media will only absorb a certain amount, then it is "full".

It becomes a question of how fast you want the phos pulled out, and how long you want the media to last before you have to change it.

I'm one of those people. My system is roughly 220gal and I just change out a cup of BRS GFO once a month. I only have to clean the glass 1-2 times per week and my macro algae barely grows.

Start with a small amount and keep checking. If you discover that your levels are not dropping or continue to rise just add more.

I'm a little less technical about how I go about it. I started off following BRS' instructions and the HC stuff is expensive. I just decided my maintenance amount would be 1 cup per month regardless of levels. Actually I don't even test them. When I notice the algae on the front glass comes back strong in 2 days I usually change it out. So far once a month is roughly when that happens.