Oh, agree 100%. BKs are like a fine tuned porche compared to the BMs... not alot of refinement, so they make up for it with raw output like a chevy camaro. There gets to be a point though where you gotta ask yourself... how much more am I gaining by paying the premium for that fine tuned item? The BM's do a decent job skimming... no doubt about that. As good as a BK? Well... technically I think the BM250 is more efficient than the equivalent BK from the wattage/air throughput ratio... but this is why I compare BMs to camaros.
Back when bubble plates by Spazz and Bill started showing up and people 'jumped in' to the latest DIY fad, there was some hot debate on bubble plate design. Many felt that simply having a cumulative hole diameter that equaled 2 or 3x the outlet diameter of the mixing pump was 'close enough'. I argued that there must be more to it... alot more. Bean got upset and told me I was applying science where it wasnt needed... overcomplicating, etc... but after making a few bubble plates to play with... I was noticing things...
Multiple smaller holes functioned much better than fewer larger ones. Look at a BK's plate and then a BM and tell me what you see.
There are pressure, throughput (air and water) variables, etc. Not knowing how many holes to drill (or a cumulative hole area ideal) can mean you end up with too little pressure behind the plate... and you end up with larger bubbles being passed here & there. Having too little holes and you end up with too much upward momentum behind the bubbles, and that bubble plate might not be giving you the advantage that it could because its pushing the bubbles to the surface faster.
After a while, Klaus shared some of this with me because he saw my posts on bubble plates. Turns out I was on to something. There are equasions for determining ideal bubble plate size and number of holes... based on the pressure, airflow, and waterflow of the mixing pump. Simply multiplying the area of the pump outlet or guessing can leave you with less than perfect results... sometimes causing more harm than just running w/o a bubble plate. What Im trying to get at is that there are some very specific variables that have to match up here.
So this is what I find odd...
ATI had the eheim 1262 threadwheel until it came to the US. Then, due to 'problems' with the eheim (seems odd because eheims shouldnt have a problem running this...) ATI had to find a new pump. Elke Müller (owner) ended up with the SICCE clone of the new Tunze needlewheel as the new pump. The thing I dont get now is...
The lph of air throughput on a BM has been increased alot by the new pumps. On a BM250 the air throughput has pretty much doubled. So one would reason that a new design for the bubble plate... perhaps a new diameter or something... would be in order, no?
Nope. Larger pumps and more power. Sounds like the Tim Allen method of skimmer engineering... which doesnt always turn out working too well.
Luckily the BMs seem to be benefiting from the 'more power' idea... this time.
FWIW, Klaus told me that ATI stole the design in a way from F-M. The designer, who contacted Klaus in the process for approval and such on the F-M designs, was not involved with the ATIs. I forget the exact details... they are all in German in my PM box...lol. But the basic idea was that the ATI design isnt as refined or calculated. There comes a point where simply blowing as many bubbles as you can into a column of water can be counterproductive... and you end up skimming out more water than you need to.