Return pump flow rate; Sicce 4.0 or 5.0

[CoryDude]

So I'm in the process of installing a new 120g tank. But, I'm unsure of what return pump to use in my sump. In the late 90's and early 2000's, it seems that everyone went with high turnover sumps like 7X - 10X tank turnover per hour. But, now I see a lot of people going with a lower turnover ratio.

This tank will be an SPS dominant tank with 2 mp40's. I want my chiller plumbed to the return pump, so I need to keep flow rate within the unit's specs. The sicce flow charts show about 700 gph at 6ft of head for a 4.0 model, and about 1050gph for a 5.0.

Should I go with the 5.0 and use a valve to turn back the flow rate, if needed. Or, go with a 4.0? Help please!

[Europhyllia]

so what are the chiller unit's specs?

[CoryDude]

Both flow rates fall within the unit's specs. About 1200gph is the max and 650gph is the min recommended for the unit.

[StevenSeas]

I think it depends a lot on what you are putting in your sump for filtration purposes. Biological media tends to need a little bit longer to work so not as quick of flow through rate is as efficient. Also skimmer flow rate could play a factor also. Really it depends on what you want to do. What I would do would be get the 5.0 and make a T in the return and on the side coming off put a valve and piping back down to the return pump chamber. This is beneficial because you can "bleed" off pressure and flow without putting back pressure on the pump which will work it harder, causing more heat and shorter lifespan. So I would go with the larger pump and start scaled back and if more flow is needed then scale it up.

[Europhyllia]

what size sump do you have?
I had a 640 gph pump on my 120 tank and with a 55g sump flow through the sump was kind of slow but sufficient. Now on the 215g tank I have the Sicce Syncra 5.0 (same sump) and flow is just perfect it seems

[Big_Pun]

run bio pellets and dont worry about it lol. but from talks with gabe he's always told mr to keep it slow. are you going to be running a sand bed or mud in the fuge

[CoryDude]

Sump is going to be a 30g long.

aggie - hadn't thought about running a T. That's a good idea! Also, didn't take into account the skimmer turnover. I'll be using a Euroreef custom 6-2 w/Sedra 5000.

Karin - Was the 640gph the max for the pump or was that the actual flow rate in your sump? I'd like to keep mine between 700-800 since the chiller seems to work more effeciently above 700gph. Have you measured your flow rate with the 5.0? How high (ft or meters) are you pumping the water? My main concern is the manufacturers seem to over estimate on their flow graphs.

Chris - no biopellets here. Still going to use the Hiatt for a while.

So far, I'm leaning towards using the 4.0. If the flow isn't enough for the chiller, then I can upgrade to the 5.0 before springtime, and just use the 4.0 on the Hiatt canister.

[Europhyllia]

Cory I have no ide how I'd measure that. I just go by the charts :o