<a href=showthread.php?s=&postid=12659806#post12659806 target=_blank>Originally posted</a> by tbone28
Assuming one runs an internal skimmer with a dedicated skimmer compartment in the sump and ATO (i.e. steady water level), and the tank drains water directly into the skimmer section, *how much* better is an External skimmer?
I'd agree that theoretically an external would skim *more* if it's direct fed, but skimmers are not 100% efficient. In other words, even though an external is direct fed, the skimmer can't process all that water with the 1st pass. Much of that water is drained out.
With an internal skimmer, the skimmer is taking in raw water since it's in it's own compartment. The water that drains the skimmer is returned to the skimmer compartment. In a sense, it is reciruclating as well.
I'm curious as to how much more an Ext skimmer would skim given these 2 scenarios.
Actually, a better way to set up the sump would be to have a seperate compartment for the water to drain into initially that is taller than the skimmer compartment, then flows over the baffle into the skimmer area. This would prevent the water level fluctuations even better. Then have the skimmer compartment baffle that is higher than the water level in the return section. The first compartment would even out any fluctuations in the overflow drainage caused by crud or air bubbles.
If you think of the proteins that are coming in directly from the overflow, a significant portion will be those that already have migrated to the surface of the water and will be easiest to skim in a single pass, and less likely to simply travel through the skimmer. As opposed to an internal where those same proteins will again end up on the surface of the sump water only to travel back into the main system until they eventually get skimmed out.
Of course, this theory of direct fed is still merely an opinion, but if the process is thought through logically it makes sense. How or earth you would be able to prove it is another matter. Do I believe direct fed to be more efficient than internal? Yes. Does it make the world of difference? Absolutely not. I did buy an internal originally after all, so even in my mind, it's not a significant difference. I'm just a logic guy, and to me, it makes sense.
I have witnessed though, that external do tend to be able to overcome the oils from foods, etc that knock the foam head down, faster than internals. The only way that I can come up with that may explain this is the higher air/water pass through ratios. Especially with a dual recirc fed off of something like a Maxi 1200, you've got a lot of air being generated in the skimmer body with a relatively low pass through of water. 1900 air/ 1100 water. The BK 200 runs about 1000 air/ 2000 water, which is typical of a non recirc.
Let me be very clear though, I am no expert, and am very much still learning and could very well be completely wrong. It is a theory only, and I happen to believe this theory to be true. Don't take it as BK bashing either, cause I still love my BK, and if I could comfortably have afforded another BK, especially a D250 or 300 Ext, that is what I would own at this moment. I also like the SM's, and very nearly bought one of the SM 250's. Actually had Brandon at Your Reef getting ready to fill out the paperwork to become a BK distributor to get one for me. Later that same day, the doctors bill for my wife's latest CAT scan came in, and Mark and I, and a couple of others were discussing the merits of a single large pump skimmer like the BK's vs. multiple smaller pump skimmers like the H&S, which got me thinking along the potential for finding a deal on H&S. We all know how rarely used BK's become available, so the chance of getting one at a serious discount(a price which I could justify to myself given current financial circumstances) was extremely remote. A week later the H&S came up for sale. Now I just need to sell my BK to pay for it.
So, do I think that the H&S is better than a comparable BK, especially external, no. I'd say the opposite is true. Do I think the H&S is better than a BK internal? In terms of production, maybe, maybe not. I really don't know. I know 1900l/air is better than 1000l/air in the same diameter body. In terms of build, quietness, attractiveness, even long term pump performance? No, I believe BK wins hands down in these areas. Would I have bought a BK 250 deluxe external for $1000 over the H&S? You bet your booty! Single pump or not. The real question is, would someone ever sell a BK 250 D ext for $1000? Not a chance.
The real question is what skimmer will I own 1, 3, 10 years down the road? That'd be a good question, and it is quite likely to be another BK eventually. Especially a dual pump version with a DC variable pump!!!! Gotta save a few nickels first.:lol:
Many of may have noticed the equipment list that I have compiled is, well, rather high end $$$$ components. After build take I, I came to the realization that I was never satisfied with the equipment that I had. Always looking to see what else was out there, buying that, and still not completely happy. As Mark can attest, I've got 2 large cabinets in the garage FILLED with reef stuff. You should've seen it last year. I decided to sell all the "unsatisfactory" items, pool the $, and get equipment that I'd be considerably less likely to get dis-satisfied with, or even if I did, would hold their resale value. Why buy junk that may get replaced in a year, just to have it sit on a shelf in the garage? I am now pretty much a high end junky. Even today, I darn near bought a Red Dragon 4.5 M3 pump to feed the chiller and fuge. That's nearly 5 bills to feed a fuge!!! Why would I even consider it? Well, it had the features that I wanted for that piece of equipment. The right flow rate at 10' head, silent, low energy consumption, dependable, quality piece of equipment that I'd be very unlikely to need to replace in the forseable future. You see the way my mind works? Now, of course the budget and common sense got the better of me, and I had in my cabinet, a pump that would get the job done very well. Damn logic and common sense!:mad2:
Anyhow, enough of that. I did pick up some acrylic tubing and a sheet of acrylic to make the silencers for the H&S, even though it'll be in the garage. Thanks Rafael.
I still need to pick up a couple of odds and ends for that little project, but it won't be long.
