Thoughts on starting GFO reactor

[thabizness]

I have a 75G mixed reef w/ a 20g sump/fuge with chaeto and skimmer. Im getting good growth from my cheato but I also have a lot of algae growing on the walls of the sump. I also have the normal film algae growing on the glass in the display and a few brown spots on the sand from time to time. Nothing bad.

Using a hanna my phosphates test 0 - my thoughts because the algae in the sump is eating it as its being produced. Just to make sure the hanna is working I tested my QT tank which has no algae to eat the phosphates and I do get a reading from that so I assume the meter is good. My Nitrates also test 0 in the 75g. I double checked the test with the QT which does register 'trates to make sure it was working. Up till now I have fed sparingly and do 10g water changes weekly in the 75.

I am increasing my feedings and adding another fish bringing the total fish population to 6.

I have a GFO reactor that I planned to add sooner or later. I am debating if it would be good to start it now or wait. I know I have phosphates because the algae in sump - I just cant detect them.

Thoughts on starting the reactor?

[Timber77]

would try to not use gfo if possible, it makes rust everywhere.
its a good for a short term fix

i also wouldnt bother testing for phosphates, you will confuse yourself with the results, if you have nusiance algae then you have phosphates... hobby grade test kits are not accurate and wont measure any bound phosphate in your system