External Pumps

[Skimmin]

I'm in the process of setting up a 120g with an 80gal sump/fuge that has an approx capacity of 65gal. I've never used anything but submersible return pumps. I had my sump drilled so if I want I can use an external pump. I've been considering using a Sequence Reeflo Snapper as a return pump. I just can't decide whether the external pump is a good choice or not. Are they quiet or noisey compared to submersibles?

[Palster]

Any of the aquariums I have seen that have an external pump are much quieter than the Mag 12 submersible pump that I am currently using. The next sump that I build will definitely be built for an external pump. Other advantages of an external pump is that they are normally more energy efficient than a submersible pump and they run cooler.

If you are going to use a Reeflo Snapper as a return pump just be aware that you will be putting a lot of flow through your sump and could have micro bubble issues. I would definitely consider putting ball valves on the discharge side of this pump so you could "throttle back" the flow if necessary. I think these pumps put out around 2500 gph before friction loss which is a lot of flow to be putting through your sump.

[mark]

Could be wrong but thought the Snapper (and Dart) were more of a CL pump than some of the other Sequence pumps. Another thing is the size of inlet to deal with (2") as usually don't want to restrict a pumps inlet (okay the outlet). The other small Sequences series are 1.5" inlet.

Other thing is your overflows, what are you good for there?

As for your question re: noise, I've got a Dart (just a like bigger than the Snapper) directly under my tank, it's quiet but not silent. During the day one doesn't notice it but as I've written before, once the kid's in bed, TV off you know it's there.

Here's a good pump list from RDO and a head loss calculator from RC that allows you to find the flow with different pumps.

[Skimmin]

Here are some flow charts that seem to make pretty good sense. http://www.reeflopumps.com/images/flow_charts.xls
I'm still unsure which one to use.
I have a hole for a 2" bulkhead drilled into my sump so thats why I was thinking Reeflo snapper might be a good choice. My tank has 2, 12" external overflows with 1, 1 1/2" drain and 1, 1" return line in each. My intention was to plumb into the pump using 2" pvc. Then run the return line (from the pump) in 1 1/2" pvc and use a 1 1/2" T, 2 ball valves, and reducers just before the 1" return bulkheads... The T would be used to change from 1, 1 1/2" return to 2, 1" returns. I thought running a pump with a bigger inlet and outlet would be a good thing but if this isn't true I'd much rather find out before I order the pump.

[fkshiu]

The Snapper is not a pressure-rated pump meaning that it is not designed to pump water against gravity (i.e. upwards). That's why most people use Reeflo Darts, Snappers and Barracudas for closed-loops where there is the pump is usually placed just behind the tank rather than a good 4 or 5 foot underneath it for a sump return pump. Practically speaking, this means that you are paying for a lot of gph that you'll never get if you use such a pump as a return pump.

You can see in Reeflow's charts that their "flow-biased" pumps like the Snapper loose more flow as head (i.e. height) increases than their "pressure-biased" pumps.

Secondly, for a 185 gallon system you do not need anywhere near the amount of flow on a return pump that any of the Reeflo pumps give you. Most people aim for a 3-5x system turnover rate for their return pumps. Faster flow has three main downsides: 1. more issues with microbubbles; 2. more salt creepa (both due to the greater splashing/flow); and 3. lowered skimmer performance because the water is simply flowing too fast to be taken in and skimmed.

All this being said, external pumps are the way to go IME. Less heat and easier maintance (provided you hook it up with true union ball valves).

Personally, I'm using an Eheim 1260 on my 165 gallon system. A little pricey, but it's efficient, quiet and dependable with the right amount of flow.

[Skimmin]

I designed my sump with a bypass style refugium and I have two drain boxes(one for each 1 1/2" drain). Each drain box will have filter media(metala) in the bottom compartment and a fine filter sock in the top compartment for cutting down on microbubbles. The skimmer is a re-circulating ASM G2 which wiil be piped back into the fuge with the gate valve and drain pipe. I agree that the pump will have a lot of flow but I'm hoping with appropriate valves and unions it will work quietly and efficiently. http://i193.photobucket.com/albums/z.../refugium3.jpg