<a href=showthread.php?s=&postid=10064264#post10064264 target=_blank>Originally posted</a> by King-Kong
Can you link to anything further discussion this issue? Perhaps actual testing that has been conducted with removing the BM plate, or perhaps testing on bubble plates in general?
Here is a pretty good look at a ATI BM250, showing it's bubble plate.
Here is one of the better shots I could get of a BK bubble plate:
Both plates seem a long the same lines. Enough so that I really doubt it would be fair to call one a "gimmick", but perhaps you've done some testing you can let me know about?
Nope, dont need to. Just look at it and compare specs... when I saw the two in person, my suspicions were confirmed. That video that sjm817 just posted is all you need to see. Look how crazy that central column is. The BM 250 for instance, might be 10" in diameter for the outer body, but the skimmer itself is really only 7" in diameter... all that outer area is for bubble seperation. So look at it... thats 1800lph of air, and almost 2000lph of water through a 7" diameter body... who cares about the bubble plate?! Compare this to a Euroreef RS250... about 1180 lph of air, and 1200lph of water... through a 8" diameter body that is much taller. The ER RC250 has half the air intake of a BM250, in a 8" diameter body... which do you think will be more turbulent? The bubble plate is a gimmick... look at the previous models that didnt use one... there is no difference. The cylinder that guides the bubbles and water upwards after the bubble plate is the same size... so its not reducing turbulence. Its like taking a garden hose and splicing a filter into it... the water flow will still be the same going in as it will going out no matter what mesh is inside the filter... its recombining everything right after the small bubble plate. Whats the point of a bubble plate, ie: bubble diffuser, if all you arent actually increasing the diameter of the passageway? Its not a diffuser, its just a strainer... a piece of mesh. Whoopie. And then, the actual distance from the 'bubble plate' to the neck in the skimmer is something like only 12" or less... and its a co-current design. That means that the contents of the BM is making a short trip to the top... its relying on the mere fact that it can emulsify 1800lph of air with water... but much of that is wasted on such a short and turbulent contact time. Then take a RC250... half the air, but its a 30" tall skimmer.... and the distance that each bubble has to travel to make it into the neck is 2x as much, and in a much larger body diameter (actually, about 25% more cylinder area for 1/2 the flow). This makes for bubbles that have a much better chance to attract and keep surfactants... so even though the 250 has half the air throughput, its using those bubbles 2x as well. The skimmate on the ATI is watery usually, unless you have the most nutrient laden water. The skimmate from the RC250 by comparison... is thick coffee. Well... its not just all about lph of air, but how you use them.
So all things considered, I would rank the BM250 at about the same level as a ER RC250 because the BM, despite its 1800lph rating, is making bubbles that are only half as effective. Compare the two neck diameters on the skimmers and you will see how similar they are... thats what it comes down to.
And then there is the Bubbleking. The bubbleplate on a BK that does close to a BM250 is a 300series, and that body is much wider (14" diameter) , and the bubble plate for that is 2x the area as the BM. An actual diffuser... not just a plate with holes in it. If you compare the two side by side, you will see how much calmer the flow in the BK is on the inside... its calm, and steady, like a froth of milk rising upwards at a fraction of the speed of the ATI. The contents of the BM250 though... its more turbulent than skimmers without any bubble plate at all.
I hope you get the main idea of what I am saying here... one of the main points of a bubble diffuser is to spread out the flow across a larger area to reduce velocity... like going from the smaller end of a funnel to the larger end. The BMs dont do this, they are running a more condensed output than skimmers without a plate at all. Simply using a plate with a bunch of holes in it doesnt do anything but act like a strainer... you need to spread out the flow for it to be effective. The cylinder that controls the output of the bubble plate after exiting the holes prevents this. The BMs run a more condensed output if anything. They are pretty much like a short beckett.
You want the BM to perform much better, prolly 2x as better with the same exact pumps? Then use a 14" diameter body for the 1800lph BM250 with a 10" diameter central tube.
:lol:
