Need help with flow rate on a sump

[Delibird]

 

I am moving my discus into a 4’x2’ 120 gallon from their 150 to give me more room in the living room. I want to set the tank up with a sump, mostly to add water volume. I just want to make sure my plan is solid before I start spending money. 

 

75 gallon sump. The 120 isn’t drilled and I don’t know if it’s tempered or not so I’m planning on doing a eshopps HOB over flow. I was planning on the PF-1000 which does 1000 GPH (I’ve read it’s better to have more GPH on the overflow than the return)

 

I will do a spray bar on the return and I want to shoot for 5x water turnover (based on what I’ve read on discus forums) I was thinking of getting the Sicce Syncra, I’m unsure if I should go with the 3.5 (660 GPH) or the 4.0 (951 GPH) It’s going to be pushing water up roughly 5-6 feet and I know the pumps don’t flow as well when they have to push the water up high. If I’m reading their chart correctly the 4.0 will have 660 GPH at 5 feet. I attached a picture of the page with the chart regarding the flow and height

 

I mostly need help with deciding which pump to go with. And if I’m over looking anything or misinterpreting anything, please let me know. Any and all advice is appreciated! 

[gardenman]

You're on the right track. Just remember to include the sump volume in the five times overturning. A large sump can add a significant amount of water to the system. And the estimated flow rate from the pumps is often a bit overstated by the manufacturers. Your return line is likely to have some bendiness in it which will reduce the flow rate a teeny bit also. The flow rates they post are often under ideal conditions with no bends, elbows, etc. that you're likely to include to get the water from the sump to the tank. Most pumps can be tuned downward in flow rate if need be but they can't be tuned upwards. Better to overbuy on the pump if possible.  Assuming a 30 gallon sump to keep the same 150 gallon water volume you now have, turning over five times an hour, you'd be looking for a flow of 750 gallons per hour at five feet in height.

[MJV Aquatics]

I've come to think that this 'rule' of 4x to 10x filtration water flow relative to tank size pure nonsense. First of all good filtration is about how well we filter the water, not how much or how fast we push water through media. Second (and I have an article on the dirty truth about filters) is that filters make water look clearer, but certainly not any purer as trapped detritus decomposes and pollutes the water.

I have a 40g sump on my 110g stock tank with a 165gph pump.

[Delibird]

5 hours ago, gardenman said:

You're on the right track. Just remember to include the sump volume in the five times overturning. A large sump can add a significant amount of water to the system. And the estimated flow rate from the pumps is often a bit overstated by the manufacturers. Your return line is likely to have some bendiness in it which will reduce the flow rate a teeny bit also. The flow rates they post are often under ideal conditions with no bends, elbows, etc. that you're likely to include to get the water from the sump to the tank. Most pumps can be tuned downward in flow rate if need be but they can't be tuned upwards. Better to overbuy on the pump if possible.  Assuming a 30 gallon sump to keep the same 150 gallon water volume you now have, turning over five times an hour, you'd be looking for a flow of 750 gallons per hour at five feet in height.

Do you know how large I can go with the pump and still tune it down to what I need? Or is that different for each manufacturer 

[Delibird]

3 hours ago, MJV Aquatics said:

I've come to think that this 'rule' of 4x to 10x filtration water flow relative to tank size pure nonsense. First of all good filtration is about how well we filter the water, not how much or how fast we push water through media. Second (and I have an article on the dirty truth about filters) is that filters make water look clearer, but certainly not any purer as trapped detritus decomposes and pollutes the water.

I have a 40g sump on my 110g stock tank with a 165gph pump.

I’m not too worried about sticking to an actual rule of 4x or 10x or whatever the internet says. Most of my “filtration” is going to be water changing because they’re discus.
 

The main reason I decided on around 5x is purely just making sure they don’t have a strong current to fight against but enough to make sure the water temp is consistent and there aren’t dead zones. 

[gardenman]

56 minutes ago, PumpkinWeevil said:

Do you know how large I can go with the pump and still tune it down to what I need? Or is that different for each manufacturer 

Reducing water flow is easy. You can simply put a tee fitting and valve on the return to the tank. One side of the tee goes to the tank and the other side goes back to the sump. Simply opening and closing the valve regulates the water flow to the tank. You waste a bit of energy but you can fine tune the flow to whatever you want that way. If you too weak of a pump you can't dial it up.

[Delibird]

5 hours ago, gardenman said:

Reducing water flow is easy. You can simply put a tee fitting and valve on the return to the tank. One side of the tee goes to the tank and the other side goes back to the sump. Simply opening and closing the valve regulates the water flow to the tank. You waste a bit of energy but you can fine tune the flow to whatever you want that way. If you too weak of a pump you can't dial it up.

Makes sense. Thank you!