Active carbon in an exterior filter.

[Gary Nelson]

How many of you use active carbon in an exterior filter? I have both purigen and carbon in mine at the moment, I am wondering if just more purigen maybe better for fert dozing and plants- would the carbon be stripping many of the needed plant nutrients out of the water?

 

[Alastair]

hiya mate, i remember an indepth thread on here somewhere where it was shown that carbon doesnt have much effect in the way of removing ferts if dosing full ei as we are adding more ferts than normal anyway. I think it was viktorlantos (could be wrong) who uses carbon all the time and has had no defficencies what so ever. i used it for several weeks when i first popped my wood in and didnt see any bad effects to plants

 

[Ian Holdich]

the problem with carbon is that it's adsorption doesn't last to long. It's life span shortened in hard water (or so i have read). It does render well as a biological filtration though. I use purigen personally and love the stuff, it remains my chemical weapon of choice.

As above carbon is negligible when removing fert from the water column.