How much carbon

I bought a little 4x8 inch media bag and some carbon. For a 30g display + 10g sump/fuge, how much carbon should I be putting in the bag? Thanks.

 

A little less then 1/2 a lb. I don't think you can have too much but thats the minimum I think

 

I thought it was measure by cups. Like half cup for every 10g or something.

 

I would use maybe 1/8th cup. You don't need much, just remember to change it every couple weeks.

 

I have always gone by a pound per 100g

 

Per change??? That's insane! Carbon is super lightweight. A half gallon of BRS carbon is only 1.5 lbs. I use maybe 1/4 cup every other week on my tank, with actual water volume about 65g.

 

I havent used carbon in awhile so maybe im a little fuzzy LOL

 

I would say a pound per 100g every 6 months, TBH lol.

 

I use 3/4 cup for my ~120gal of actual water volume (ROX carbon).

The type of carbon is also important.

BRS has a nice calculator for this: REEF CALCULATOR - English