followup Thats why nobody uses a skimmer on a freshwater aquarium.
Actually, they are used in FW applications, but the
hardness of the water is very important for effect. The harder the better the performance.
Foam fractionation is one of the oldest methods of *chemical* filtration we have.
Charles has it
nailed.
Hey guys!
what about using the central column part without the skimming component to oxygenate, maybe setting the device in the main res and let it run or cycle it? i have a lot of oxygenating features built into my rdwc system already, but always looking for ways to do it better/cheaper. check out my thread in the dwc forum.
cheers! jack
If your goal is to increase dissolved O2 levels then surface agitation is the way to do it. Charles did a great job of explaining why your water/res is limited in how much O2 it can hold. What I don't think you've picked up that he put down is that the
only place where CO2/O2 exchange occurs is on the
surface of the water. Therefore, adding a venturi (the snorkel) to a powerhead will only create microbubbles, it will not increase the dissolved O2 in the solution. Cooling the solution will automatically allow it to hold higher levels of O2.
Canister filter, I would stick with an airpump. The type of bacteria used in aquariums reduces ammonia and nitrates and nitrites which are some of the nutrient forms we use .
Also would take at least a month to colonize
Disagreed. What bicycle is talking about is basically a reaction tower. It doesn't necessarily have to house nitrifying bacteria, but when the solution is trickled over the media (let's say bio-balls) then it cannot help but outgas CO2 and take up O2 because of the incredible increase in surface volume. Surface volume is where it's at if that exchange is what you're after.
But let's say that somehow his res is colonized by some sort of nitrifying bacteria. They take NH3/4 (ammonia) and oxidize that into NO2 (nitrite). The first form is definitely a usable form of nitrogen for the plants, but the final product, NO3 (nitrate) is also perfectly usable *and* will not be reduced without either water changes or a region within the system with sufficiently slow flow so as to allow an anaerobic region, such as a plenum. Those anaerobes can then break down NO3 into its constituent components--nitrogen gas and oxygen, and those are released into the atmosphere.
Jack, I see you've moved away from foam fractionation, which I think is a good idea because what it would mostly do is remove the very nutrients you just added. Keep it simple--surface agitation with good air exchange wherever the res is. Bubbles moving through the water absolutely do not increase dissolved O2 by any significant amount as they don't have enough surface area. Also, they attract hydrophobic molecules (this is how foam fractionation works, via hydrophilia/hydrophobia of certain molecules) onto the bubbles and what do you get? A whole bunch of nutrient rich foam.
