Coug the brand new sand and or gravel you put in your tank is already at saturation level before it ever makes it into your tank. What happens in our tanks happens in the wild the same way, just look at the florida bay problem.
Anyway the key is to not allow it to come out of solution. The way it comes out of solution is by a reduction in PH in the lower end of the bed. In using larger particles and good water flow and in keeping the bed areobic we are not allowing the ph to drop in this upper zone. What this gives us is a well areobic bed (with all the critters everyone want) and with the ability for nitrification and for denitrification lower down and in the plenum zone. The main source of Phosphate problems are not really associated with the disabsorbtion of the sand particles but in reality is with the organic forms that are assocaited with detritus/bacteria and vegitation. This is where we really need to go after controling it. So far we have come up with a few good plans. With the use of larger particles we are going to eliminate alot of the clogs that occur in finer substraights, it is also going to allow for a much larger and deeper areobic zone for areobic nitrification. the flow coupled with size of particle is going to allow for easier migration of food sources to the anaerobic zone denitrification. Now were are going to have phosphate build up still in the bed, but nowhere close to a finer substraight bed. This cycle as it is with any substraight is basically phosphate to algae then to animal(bacteria) then then back to algae again. In order to control it we must break it, export it and control its input. So input is by watching what we add (ro/di, perservatives in foods, over feeding and so on). In controling it we have the above larger particle , keeping the bed areobic, sucking out the excess and end product detritus through a plumbed system in the plenum zone. In breaking the cycle, we again have the keeping the bed zone areobic, stirring the bed occasionaly to remove excess, and in a remote location we allow fo no light, no light means no algae, which means the phosphate stays in animal form and can be exported via the suction (in animal form I am talking bacteria only).
Anyway that where I see us so far???? whatcha think.
Doug
Quote:
|
Back to the cleaning topic. Mike, if you remember in talks with Sprung and other threads, there seems to be not much sign of a detritious build up, in a correctly functioning system. Esp. if siphon cleaning of the surface is done regular. Also we wondered about the dissolving gravel, near the bottom screen, from the lower ph. Remember we wondered about it plugging up the screen, but it seems it just keeps dissolving, perhaps falling through and then dissolving completely
|
You bet Doug. With the larger particles and good water flow I dont even think stirring would be need. On the dissolving, thats the way I always saw it, and again I think the occasional sucking from with i the plenum should pull down the finer stuff, suck out the excess detritus and export the end product that would be building in the plenum zone. The down point of this suction is temporary loss of the anaerobic zone, but that should come back quick, man you could even reverse the pump and inject you reactor effluent.
MIke