Barry Grossman said:
hhmmmm.... Nice to get some feed back given that I'm stuck here in the jungle 3/4's through a mad project that can only get more difficult. Thanks fellas and I will come back once I've reviewed the suggested sources. ...............................
One of the problems I have here is that I can't source large diameter acrylic tubing. I've been thinking about simply using 16in PVC pipe lined inside with Acrylic sheeting (I worry about PVC and algae - all the plumbing is in polypropolyne) for the body of the skimmer unit(s). What I remain confused about is which type of skimmer to use. I had palnned on trying to produce a simple venturi driven skimmer but I worry about the poor little planktons being frced through that little birthing canal every hour or two. Maybe a big but simple counter current skimmer using an airstone and blower?? Or maybe even an ETS/downdraft system?? see...I'm confused.
....................... Assuming a moderately efficient skimmer system, would one plan to 'turn' the tank contents every hour (AJ Nilsen), every 3 to 4 hours (as appears with some of the Deltec skimmer specs) or less frequently?
Anyway, any and all advice is appreciated and I will now go and follow up the suggested sources...Thanks Mike & LDRH
Mike,
I wouldn't worry about hurting the plankton, especially with as large a pump as you will need to feed and recirculate with. The theory of plankton being hurt from going through a centrifugal pump is largely a bunch theorectical bunk. If you could get a large microscope, I'd bet you'd see the plankton smiling as they came out the other end; as if they just went to Disney World and came off a roller coaster ride.....
Keep one thing in mind,....you can only undersize a skimmer. After couple of weeks, after giving it and the tank time to stablize, that is easy to figure out. Does you skimmate stop or slow down as the skimmer pulls out the protein from the life load. If it just continues to pull skimmate without stopping, it is undersized.
When I feed my skimmer pulls out the residual protein within an hour and fills my container. It pulls out very little between feedings. Too small a skimmer pulls out protein slowly and give the proteins a chance to break down and pollute the water.
Virtually all plastic material is inert to salt water and can be used for construction as long as it has the structural strength to hold the pressure.
Stop when you see a construction site laying water and sewer pipe. Ask the forman for a piece of scrap and pay him a few bucks. Large PVC or poly pipe used in contructing sewer and water lines is ideal. Keep you eyes out for any place they are laying new water or sewer pipe to pick up a 6' section of scrap to use to build a skimmer. It doesn't need to be clear, infact clear encourage algae growth inside. If you can pick up plastic sheeting to make a square shape skimmer that is fine too.
A skimmer is the easiest piece of equipment you can build. All you want to design for is fine bubbles, contact time, and flow rates. Just copy the basic dimensions used for one of the large commercial systems. Taller is better.
Also, a skimmer doesn't have to be a single large unit; it can just as easily be multiple smaller units sitting side by side and run parallel. If you can only find cheap 6" or 12" pvc pipe to build it with; install three or four identical smaller systems side by side with a single feed pump. The nice thing about that is you can easily increase capacity by adding another section in parallel.
The cheapest way from both the component and operating cost stand point is using a good little linear compressor and airstones, like Majoreef has done. Just pick a quiet compressor so you don't have to put it a 100' feet away because of the noise. :badgrin: You can always design it and install connections so you add an ejector and pump to test out other feed systems. Just keep a gallon of vinegar around with replacement air stones soaking in it. Design the skimmer so the airstones are easy to remove and clean.
If you live close enough to the water, buy a good pump and lay some piping. Then you can forget about all this skimmer stuff.

Good luck and post pictures......
