Filter system design questions

MacFanMr

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May 21, 2006
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As I rebuild my tank (now 240g), I wanted to redesign my filter system. Two cannister filters only got me 600gph (wo/media) which is far from the recommended 5+ times-per-hour tank turnover rate.

I'm planning to go with 1" PVC plumbing and a pump rated at 1600+gph. When under load, that should achieve the desired 1200gph. From the pump it would go into a mechanical cartridge filter, a heater module and then a fluidized bed filter before returning to the tank. For CO2 I thought I would switch to a venturi injector.

Over in the 1600g aquarium thread, Ocean Clear filters were recommended in some of the later discussion. Would I be better off going with that instead of a Lifeguard brand cartridge module? Are Lifeguard modules ok in general?

One of the OC filters comes with a UV module. This will be a heavily planted FW tank, but we're planning to have Discus. I've never used UV in a tank before as I heard it can kill desirable things in the water. Is this wrong? Should I consider it for Discus due to their cost and sensitivity? Should I go with an integrated one like OC or a dedicated inline module?

Looking at fluidized bed filters, there is a negligible price difference between the models which cover 300, 600 and 900 gallons. While the smallest should cover it, is there any harm in getting a larger one since it's nearly the same price?

I've heard that FBF's can be a problem if the power fails as your bacteria begins dying off immediately after the substrate settles. Some models appear to have four ports. Would it be worth using two to put it inline with the filter, and use the other two to create a short closed loop with a small pump that can be run on uninterruptable power supply so the sand can be kept in suspension in the case of a power outage? That also raises the question, how do I clean the cartridge without stopping the filter? Create a bypass loop?

Also, does having an aggressive mechanical filter before the FBF decrease the usefulness of the FBF? Some mech filters say they filter to 5 microns, is it possible to filter out too much of the stuff we want to be consumed in the FBF?

In the 1600g thread, you mention using venturies before a reactor. If you're using a reactor, why use a venturi? Is a venturi not efficient enough without a reactor chamber? I will have a high CO2 loss due to the bog area and some surface agitation.

I heard that MagDrive pumps basically last forever. Apparently the QuietOne pumps are also very good and are more energy efficient (gph/watt). But the smaller QuietOne pumps I've used didn't seem terribly rugged. The cost is comparable, which should I go with?

Thanks.

Michael
 

Tom Barr

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I'd use the OC canister filters!
Much better over time.

I'd suggests a venturi after the return pump with a loop to by pass and use two valves to throttle between the loop(one valve on the loop, one on the main line after the first cut off for the loop but before the second return part of the loop).

You can adjust things to get a froth of mist or back off from there.
Mag drives are fine.

Regards,
Tom Barr
 

MacFanMr

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May 21, 2006
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Ok, so OC cannister filter alone? Or in combination with a FBF? I understand that you can't do better than FBF for biological filtration.

What about UV? Good/bad for FW? Recommended for more sensitive fish?

Thanks.

Michael
 

MacFanMr

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May 21, 2006
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Hmm... doing some research I'm finding that FBF require a relatively slow flow rate. Do you just add a bypass and flow only part of the water through the FBF or do you run multiple FBF units? I see they make larger ones, but they get much larger and MUCH more expensive in a hurry.

Michael
 

2wheelsx2

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If you are only switching over because of flow rate, have you looked at a Fluval FX5? 900 GPH flow rate (w/o media). Two of those would get your more than you need. Pricing is about the as an Eheim 2028.
 

Tom Barr

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A larger Ehiem 2260 ought to do fine also.
I'd use one of those and an OC with the UV, turn the UV on once a week for a day or two after the water change.

Regards,
Tom Barr
 

MacFanMr

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May 21, 2006
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Flow was one reason. I also liked the idea of the FBF and the ability to put pretty much anything in the tank without worrying about biological filtration. Of course it seems to come with its own worries.

I found this DIY FBF which looked really neat:
DIY - Acrylic Fluidized Bed Filter

I'm thinking about trying to build something like that out of a cone bottom tank like this:
- Plastic-Mart -

Michael