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De nitrification coil


paul b

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Biopellets can certainly reduce all nitrate to zero along with some or all of the phosphate resulting in starvation of corals. BP's work great when you're feeding lots of food to the fish and/or coral and don't want to deal with nitrate issues.

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I have not had much luck with the biopellets rob but your'e idea with the wet dry sure worked,  the biopellets thing is at my brothers 150 gallon but again I'm not impressed so lets try this coil, nothing  works anyway so why not try?

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I tried bio pellets last year and almost killed my corals.  My tank looked lousy and I threw them out.  Not going to try them again but I am not quite sure what they did but my corals didn't like them even though my nitrate didn't do down appreciably.

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to be honest, it would be very hard to pinpoint biopellets or anything else as the sole item that almost killed your corals. I believe the use of biopellets and lack of food for corals could be to blame for almost killing them. Sometimes they take a couple months to work though.

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to be honest, it would be very hard to pinpoint biopellets or anything else as the sole item that almost killed your corals. I believe the use of biopellets and lack of food for corals could be to blame for almost killing them. Sometimes they take a couple months to work though.

As a self professed expert, I've been able to kill corals a LOT faster than that!

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I don't think I actually lost any corals that I can remember but they and the entire tank looked lousy.  I threw out the pellets and now I may need to move because my corals are growing up the walls and forcing me out.

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  • 11 months later...

Vodka dosing with the coil seems like a pretty cool idea. Any updates?

Someone mentioned the risk of hydrogen sulfide. Maybe you could aerate the return water vigorously if this was a concern.

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Airating the water would not eliminate the hydrogen sulfide. I removed the coil because it wasn't working fast enough. I am working on something else right now and will report on it after it either works, or fails.

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I can't wait to see what you've got cooking next.

Have you seen anything about DyMiCo? Seems similar to what you were going for, they use carbon dosing with denitrification. Rather than skim the resulting bacteria, they let pods eat them, then the fish or corrals get to eat more pods.

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From what I gather, they (DyMiCo) monitor redox in the effluent from the denitrification to control flow rates and carbon dosing. Redox potential below a certain point would allow hydrogen sulfide today form, so they stay above that level with less dosing or higher turnover. In the right redox range they get denitrification and also nutrient uptake into bacteria or plankton. The water gets recirculated through anoxic substrate and pods thrive above the substrate. Some of the pods make it back into the display to become food.

 

The feedback control in their system is probably beyond my DIY skills but I was thinking about whether manual adjustments could get to a workable version of this concept. I'm imagining a reactor in the sump area with a slow feed to / from the sump, carbon dosing, and an under gravel filter to circulate the water through some rock rubble or similar substrate. Reactor would be covered or sealed to keep oxygen low in order to encourage facultative denitrification. Redox could be monitored with a Hanna checker and I could try to tweak the flow and dosing to stay above the hydrogen sulfide territory (research needed here). Something like a 10 gallon reactor paired with a 180 gallon system (tank and sump total), aiming to run perhaps one tank volume per day through the reactor.

 

Sorry for the thread jack. Your experiments got me thinking more about this concept. I might start my own thread once I've had a chance to look into this some more. Any thoughts at this point would be appreciated, though just writing it out was helpful enough!

 

One question, if hydrogen sulfide can't be removed by aeration, is there another way to get rid of it? Activated carbon maybe?

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Here is what I found out:

Quote

Treating the effluent air stream with activated carbon has been found to be one of the best ways to remove hydrogen sulfide. Most standard activated carbons have little capacity for H2S. However, General Carbon carries both impregnated and non-impregnated high H2S capacity carbons. The weight on weight H2S capacities for these products can range from 25-50%. Here is the link to our high capacity GC Sulfursorb Plus.

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A couple of university extension publications suggest using activated carbon or aeration to get hydrogen sulfide out of drinking water. With the caveat that aeration might let other sulfur compounds form from reactions with oxygen. Maybe if I pilot this I should build in an aeration or filtration stage. Have to make sure it doesn't kill the pods though.

 

Sources:

 

http://extension.psu.edu/natural-resources/water/drinking-water/water-testing/pollutants/hydrogen-sulfide-rotten-egg-odor-in-pennsylvania-groundwater-wells

 

http://extension.uga.edu/publications/detail.cfm?number=C858-15

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