Ceramic rings in the 404s baskets, and I have CRs in the media container on my mag 350. From what I have learned on MFK your Bio filtration is so very important.
Filtration for 125-gallon Aquarium
- Thread starter ian8834
- Start date
Pack the carbon chamber in the Magnum with filter floss for mechanical and use the 404 for bio, put as much biomax in the 404 as it will hold but dont remove the sponges in the 404, pull out the carbon and ammonia packs if it has them and replace with biomax.
I dont use any, I suppose if your water is crappy from the tap you might need it but IMO it is just a waste of money. I dont use ammorid or whatever they call it because my bio should do that for me, I dont run carbon because I see no difference without it as far as water quality goes unless I am tring to pull medications out and if that is my goal I do a heavy water change first. Carbon and ammorid?? crap just takes up space and money IMO in day to day filtration.
Carbon is not needed, some use it to remove medications from there tank. There are others who use carbon because it may help with the smell of the tank. Most aquarist do frequent water changes that reduce the impurities in the water so no carbon is needed.
Fill the media chamber of your magnum with Biomax or Efhisubstrate and continue using the blue filter sleeves, this will give you added bio filtration.
Fill the media chamber of your magnum with Biomax or Efhisubstrate and continue using the blue filter sleeves, this will give you added bio filtration.
ive got a fluval 404 in my tank and i cant give a single complaint about it.best filter ive ever owned.
I've got 3 Magnum 350s on my 125. 2 have pot scrubbies stuffed in the chamber and the sleeve over that, the third has ceramic rings inside with the sleeve. No issues. Not a very heavily loaded tank though and I change 25% water weekly. I'll change one of them out occasionally with the water polishing insert too. 
