Quote:
Originally Posted by
CBRS2K 
Hi All,
I'm new to this hobby and looking to build my first pond. I am in the process of putting together my equipment list. If I decide to go with a pressurized filter set up, I am trying to decide between the Polygeyer and Alpha 1 offerings. From a sizing standpoint, I am looking at the units that contain about 6 cu ft of media (polygeyser DF5/6 and Alpha 1 6.0 units).
My pond specifics (at least on paper) are as follows:
- Approx. 6000 gals
- What are the pond dimensions - length x width x depth?
- 2 4" Bottom Drains and Skimmer pairings feeding 2 independent settling/pre-filter chambers
- Depending on the answer to #1 above, 1 BD might/might not be enough
- How large are the settlement chambers planned to be?
- The settling/pre-filter chambers would then feed into a manifold connected to the pump, feeding the pressurized filter
- If two BDs are used, use two separate parallel systems
- Exitting the pump the flow would need to feed 3 "shear" falls with a total width of approx 72"
- I have attached a picture (albeit not very clear) of my waterfall. The width of the falls before splitting to the two weirs is approx. 30". The two weirs are 14" and 16" respectively. They are fed by an 1/8th hp Aquaflo which puts out 3600gph at 4.5' of head. The pump feeds a model 2000 Spirex vortex, gravity fed to a 155 gal Kormex tank with 8 vertical pieces of J-mat. The falls is gravity fed to the tune of about 3150gph. So, if you are going for this type of flow on your waterfall, you would need to upsize your flow to at least 6000gph. Doing so, would make a good candidate for installing a Bakki-type shower system at the top of the falls. That would give you some very nice bio following your SC-Pump-Pressurized filter situation.
My questions are as follows:
1) Has anyone done any type of comparisons between the performance of the Polygeyser and Alpha 1 units? I've heard some pretty good things about the Alpha 1 but not a whole lot about the Polygesyer (but the concept sounds interesting)
Unfortunately, haven't got any data on them. I only install the Aqua Ultima on customer ponds where necessary.
2) Does anyone have any information on the flow restrictions (feet of head) that either of these filters place on a system? I hear that both are "low head" systems, but I would like to get some numbers that i can use to help with pump sizing requirements
Most advertise that they're designed for 'low head" but in practical application, once they get "seasoned" they cause a tremendous amount of head pressure, thus loss of flow.
3) I understand that in order to support the (total) fall width that I am looking to build, I will need somewhere between 3500 - 7000+ gals/hr of flow. Only thing is, I don't know what a 3500 gal/hr flow would look like (for this fall sizing) so it's hard for me to tell if 3500 gal/hr would be "sufficient" or if I really need to be shooting for the upper end of the spectrum. I don't want to have anemic looking falls. Can anyone help me with this?
See above comment about the waterfall
4) I'm debating between plumbing a single (larger) pump into my system, or setting up 2 smaller pumps to provide for a little greater flow and provide me with a built in backup, in case one of the pumps should fail. If I go with a dual pump set up, I think that I could realize some additional savings by shutting one of the pumps down in the evening and during the winter months, where I'm guessing that waste production would be reduced. Each pump would be sized to cycle the pond at either a 90 minute or 2 hour interval. Is logic regarding a 2 pump set up "reasonable"?
Running two separate systems (redundancy) is always better than one big pump trying to do the job. You're thinking is right about the second being a back up but don't ever turn one off for the sake of electrical savings. By the right size pumps to start with, shop for reliability and efficiency and you'll be much happier in the long run.
5) If I go with a 2 pump set up, I think I've read that hooking the pumps in "serial" fashion would maintain a consistent flow rate, but greatly increase (double) the head pressure the system is capable of. A parallel set up would increase (double) the flow rate, while keeping maintaining the head pressure limitation of a single pump system. This all sounds reasonable. However, I saw a set up where someone had a serial pump set up where it "looked like" flow rate increased when both pumps were engaged. Does anyone have any experience with this?
I've heard of it but never used it. If you run two systems, and you want to use a pressurized filter in the middle then use 2 Aqua Ultima 6000 units. You could get away with two 1/4hp pumps and they would backwash these units just great. I know, because I have installed over 10 systems with this configuration and all are working just fine - no problem with backwashing either (provided you do PROPER routine backwashing).
Mike
Thanks in advance for your help.