<a href=showthread.php?s=&postid=9059586#post9059586 target=_blank>Originally posted</a> by gcarroll
You compared dart NW skimmer to a RK2 skimmer with a pump pulling 5-10 amps. The smallest RK2 skimmer with that size pump is 36" in diameter 10' 6" tall, it has a dual automatic wash down system. Rated capacity is 28,000 gallons. Flow through the skimmer is 9,300 gph with nearly 2 minutes dwell time. It is also desinged to be run with a 1000mg ozonizer. Retail price is $6299.
Bingo, we are talking about the same skimmer.
1. Ratings Mean Nothing. 28,000 or 280,000 can be put that on anything, it means nothing and is so subjective it’s ridiculous. 7000 would be a stretch for that skimmer IMO.
(Based on the rating for that size skimmer 36â€ÂX 11’, and pulling 220 scfh max of air, my 8†dia 7’ tall Mazzie venturi skimmer pulling 40 scfh which is 1/20 the size/volume, and has 1/6th the air intake, if going by their calculations should handle over 1,400 gallons by volume, and/or 5,600 gallons by air intake. 15 years ago that would be in line with common school of thought when dwell time was thought to be so very important. Personally if I put my skimmer on a 500 gallons reef would be pushing it.)
I agree with you as to a lot wholesalers use RK2 venturi type skimmers on huge systems. BUT, they also do 33% water changes WEEKLY. So how good dose a skimmer have to be.
2. Can it “process†a large amount of water? If you can call it processed. The way I see these skimmers commonly running you can almost see through them. You can tell when someone is on the other side of one. The bubble density sucks, looking even at the photos above of the other venture skimmers you see the same poor bubble density. So because water goes through one does it mean it was processed? How much water actually has air interface? 3%? 6%? Id say less than 6%
Again if you don’t buy the idea that Air water interface is the most important factor in skimming, than you probably would not ever agree with me
(If you don’t agree with air water interface being the most important skimmer factor, I would suggest you research that with Randy Holmes, in his articles or in the Chem. Forum. he dose a much better job than me explaining that.) (doing the math is outside of what im willing to do here, but if you don’t buy the interface the math would not make since anyway.
3. I never said BK was a bar gin skimmer for a large system or a small system. I did say My Reef Creation dollar for dollar is. Their big Quad recirc skimmer is one of the Up front values Skimmers out there.
(28,000 not in my book)
7000 (maybe, if you really slow down the flow throw enough to get some kind of interface.)
A. RK2
Price - approx $10,000 (retail is only $6,299 but I'm not into lifting so I added more to pay for set-up)
watts - approx 2000
B. Three MR6 R quads (ball park) $3,000 - $4,000
About the same Watts
Basically these types of skimmers are no different than the old top fathoms skimmers about the same air to water ratio. I think you would agree that top fathom skimmers are far out performed today by ER, Deltec… The reason is AIR Volume, bubble density, air to water ratio, interface.
Theirs nothing magical about these big skimmers. just because a big facility uses them only means that big facility uses them.
It is not a different ball game at all. Same bubbles doing the interacting with the same water have the same results big small... good is good and bad is bad
I don’t think that Public Aquariums, Wholesalers, Retailers, set the bar in the performance area for any kind of equipment. I think most Improvement in equipment… in the Aquarium industry comes from the hobbies and work their way up.
