Pool system parts and flow rates

[HTC]

I have been quoted for the following parts for my pool which has approx 30m3 water.

 

I calculate a required flow rate for sanitation of 3.75m3/h if I plan to run the pump for 8 hours a day.

 

Pump: Astral Alaska Plus 1.0Hp (flow of 18m3/h)

 

Sand Filter: Emaux MFV20 (20") Top Mount (flow of 10m3/h)

 

UV: Emaux NT-UV40-T (flow of 20m3/h) or Astral Helios UV LP PE (flow of 10m3/h)

 

PH Control: Exactus feed system (5m3/h)

 

CL Control: Exactus feed system (5m3/h)

 

I'm worried about the pump being too strong at 18m3/h when the sand filter is only 10m3/h and chemical control systems at 5m3/h.

 

What do you guys think?

[grollies]

8 hours ago, HTC said:

I'm worried about the pump being too strong at 18m3/h when the sand filter is only 10m3/h and chemical control systems at 5m3/h.

yep

[HTC]

So how much more flow should the filter have compared to the pump?

Looking at system diagrams the auto-dosers don't actually sit inline with the main pipes, so am I correct in thinking that the flow rate of them isn't so important?

[Valentine]

3 hours ago, HTC said:

So how much more flow should the filter have compared to the pump?

Looking at system diagrams the auto-dosers don't actually sit inline with the main pipes, so am I correct in thinking that the flow rate of them isn't so important?

Should be able to tee off the auto dosing systems from the main return line & insert valves so you can regulate a lower flow through them

[grollies]

On 7/25/2019 at 10:09 AM, HTC said:

I have been quoted for the following parts for my pool which has approx 30m3 water.

 

I calculate a required flow rate for sanitation of 3.75m3/h if I plan to run the pump for 8 hours a day.

 

Pump: Astral Alaska Plus 1.0Hp (flow of 18m3/h)

 

Sand Filter: Emaux MFV20 (20") Top Mount (flow of 10m3/h)

 

UV: Emaux NT-UV40-T (flow of 20m3/h) or Astral Helios UV LP PE (flow of 10m3/h)

 

PH Control: Exactus feed system (5m3/h)

 

CL Control: Exactus feed system (5m3/h)

 

I'm worried about the pump being too strong at 18m3/h when the sand filter is only 10m3/h and chemical control systems at 5m3/h.

 

What do you guys think?

You should be looking to turnover your total pool volume a minimum of once per day. So for 30m3 in 8 hours you'd need a pump capacity of 3.75m3/hr. Add say 25% for flow loss through filter, pipe, valves and fittings you should get a pump with a flow of around 5m3/hr. It then falls into line with your other equipment. Plus a lower electric bill.

[alacrity]

If you restrict flow, the pressure increases before the restriction. So, the operating pressure of your pump and filter comes into play. Post filter would be o.k.

[HTC]

9 hours ago, grollies said:

You should be looking to turnover your total pool volume a minimum of once per day. So for 30m3 in 8 hours you'd need a pump capacity of 3.75m3/hr. Add say 25% for flow loss through filter, pipe, valves and fittings you should get a pump with a flow of around 5m3/hr. It then falls into line with your other equipment. Plus a lower electric bill.

So with a 25% increase that brings the required capacity to around 4.7m3/hr.

 

So this small 0.5hp pump with a flow of 10.4m3/hr should be more than enough?

https://www.winwinpoolshop.com/en/product/24696/alaska-plus-05-hp1ph-220-v-

 

I can't see pumps with a lower flow.

[HTC]

If the flow rate of the pump is higher, would that mean the water circulates quicker meaning a turnover of more than once per day?

As long as the other parts don't cause a restriction, that should be okay?

[grollies]

22 hours ago, HTC said:

If the flow rate of the pump is higher, would that mean the water circulates quicker meaning a turnover of more than once per day?

As long as the other parts don't cause a restriction, that should be okay?

Yeah, there's a need for practicality in all things. 10m3/hr pump should be ok for the filter and UV kit.

 

Re the pH and CL controllers that amount of flow won't affect them mechanically (as it would have for 18m3/hr going through a 10m3/hr sand filter), it's just they will only be able to treat 50% of the water flow (at 10m3/hr).

 

You are right as well, the more turnover per day the better.