Carbon/gfo

How often do you change your carbon and gfo, earlier this year started running bulk carbon and gfo to help with phosphates. Was changing out every 2 wks at first, everything under control, change once a month now?! 120g aquarium

 

I am in the process of determining this for my 29 gallon. I am running carbon and GFO in the same reactor, 10 tbs of carbon packed and 6 tbs GFO tumbling. 3 weeks today and I keep testing the water coming out of the canister. If I go 4 weeks I think I will go ahead and change it rather than try and figure out the exact amount of product as well as time. I don't like to waste anything, but at the same time after a month I want to clean those sponges etc.

 

Yah, I have the quantity that my lfs told me to go with, but as far as timing how do you really know when it has been "used up". Just running in bags in my some under some flow.

 

I just change it out monthly.

 

If you start to get some algae or at least some more film on your glass, etc. that's a good way to tell that it's time. I usually go about 3 weeks but each tank is different. My tank will start to show that it's time - more film on glass, water clarity a little off, etc....I know it sounds bizarre but your tank starts to "talk" to you and you can tell when different things need to be dealt with.

 

If you run it in a reactor, test the water leaving the reactor. When it reads more than 0 for phos, you know that your GFO needs to be changed. If you run it in a filter bag in your sump, etc, it would need to be replaced when your overall phos level started to rise.

I run carbon and GFO in separate reactors. I run bio pellets as well, so I like having the ability to take the GFO off line and still run carbon.

Also, carbon and GFO "deplete" at different rates. A little bit of GFO can go a long way. Pre-biopellets, I could go a couple of months without my phos rising. Meanwhile, I swap out carbon every 2-3 weeks even using high quality BRS rox carbon. If I ran them in the same reactor and swapped media every time the carbon needed replacing, I'd be wasting a lot of GFO.