Best fully submerged biological media

[deepseadan]

Hey guys, I had a reef for the last 15 years and just shut it down. Tired of all the excessive maintenance, high cost and constant battles with issues. I'm going back to freshwater. I've had many freshwater tanks in the past, but I've always had hang on back filters or sumps with bio balls and drip pans. I would like to use my current sump which has a huge refugium section in the middle, but the bio media would have to be submerged. What's the media choice for fully submerged media? Sand (worried it might get dirty in time and is tough to clean), bio balls, ceramic blocks, lava rock, or ?? I plan on keeping large fish and my tank is 150 gallons.

 

[sealife]

In my opinion, 'marine pure' has some of the best bio media. Extremely large surface area.
Here's a link:

MarinePure™ Technical Information

Enjoy.

 

[Mebbid]

Honestly, in a setup like that you could use any type of bio media you want and get similar results. Hell, I'm sure it would work if you filled the sump with aquarium gravel.

The ceramic rings are currently one of the most popular choices for filter media. I would however avoid bio balls or lava rock because there are issues with both of them.

 

[Qozux]

I would however avoid bio balls or lava rock because there are issues with both of them.

What issues?

 

[Mebbid]

What issues?

Lava rock can potentially contain heavy metals that can leech into the water. Large amounts of it in a tank could prove problematic.

Bio balls are designed to work in a wet / dry trickle system and are made to maximize aeration. The downside to their design that they are very smooth and won't hold large numbers of bacteria like other medias will.