I want to change out one of my AC 50's for a magnum HOT with bio media, and the foam sleeve. How long do I need to let the HOT run before it it seeded, and I can remove one of the AC's?
I would run the old filter along side the new filter for about 2 weeks. After removing the old filter, keep a close eye on your parameters just in case of a mini cycle.
You should run them in conjunction for at least 2 weeks to make sure the new filter is seeded. You could also take the bio-media from the AC and put it in the new HOT. This way, you could just replace one of the AC's with the HOT immediately.
I would only be able to put the bio media in as the sponge and the carbon would not fit. Thanks for the sugestion though. One of my concerns is that the biomedia in the AC isn't touching enough water. I will probably remove the carbon from the remanining AC, and put in the bio media from the one I'm replacing. This is a heavily planmted tank and I don't believe I need to run the activated carbon.
NO but that carbon is notorious for harboring more beneficial bacteria then any bio media. Make a hole in the AC carbon bag and take some out (1/3) to make room to squeeze it into the carbon basket or just pour it inside, use a little floss to make up any difference.
But no matter what you use sew yourself up a a tube sleeve made of blue/white bonded pad for the inside strainer and use the large hole strainer not the slit strainer, you'll be glad you did. See below thread.. http://www.aquariacentral.com/forums/showthread.php?t=215732