Reactor Sizing Question

[TimIA]

Question on reactor sizing for GFO and Carbon. If you are planning a total system volume of approx 600 gallons(probably less but lets use 600), you would think one of the larger reactors like the MR10 would be a good fit. But then you go out to BRS reef calculator and find out that you only need about 3.75 cups of the High grade ROX 0.8 carbon and only 4.7 cups of the high grade GFO. So that puts you into the MR5 tall reactors. So which one would be best? The smaller diameter reactors would require a slower flow rate compared to the larger reactor for a given tumble rate I would think but 4 cups of media in the larger reactor seems like over kill. Is it? I'm leaning towards either the MR5 tall or MR10. Any help would be greatly appreciated as I have never used reactors. No space limitations either.

Thanks

 

[ctenophore]

With no space restrictions, a taller, narrow reactor is better than a shorter, wider one. The narrower one will give better contact time for a given volume of media.

Rox 0.8 is good stuff, but it is so small that it can fall through the foam over time. This isn't usually a big deal as it won't make its way into your tank. If you use a smaller pored retaining device (e.g., nylon screen or mesh bag) then that can clog a lot faster. So it's sort of a balancing act. Personally, I have used Rox in the past but stick to lignite carbon now as I see the same results with both. I wouldn't hesitate to use it though, just be aware of the issues re: media reactors or mesh bags.

If you plan to use both Rox & high capacity GFO, then MR5 tall will be plenty for your system. Hope this helps!