Return size ? with RFG (Random Flow generators) from duel return pumps with UV.... - pluming setup - advice please..!

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Hunua - New Zealand
What size return pipe / hoses? 1/2inch ?

What return size with RFG (Random Flow generators) from duel return pumps with UV....
RFG - are they any good ones?

Tank details
85G DT and 35G sump (based on 50% volume) = 120G total water volume. Or 454 litres.

Over flow 1200GPh - Modular Marine - with 3/4" bean animal.
X-1 Filter roller
Duel 2 x DCP-3500 pumps. - 925GPH each
Deltec 600i skimmer
Bubble Magnes - CR120 Calcium reactor feed with a FX-STP2 dosing pump - yet to purchase...

Turn over ... x6

DT turn over x 6 = (454 litres) = 2724 litres per hour / 2 = 1362 litres per pump.
So I guessed 1362 litres SHOULD be possible from 3500 litres rated pumps? yes?
1362 liters = 359 GPH per pump.


Pump 1 - DCP-3500 will feed a Lifegard 3" x 55w UV @ 350GPH - ideal flow rate from what i have read.
Pump 2 - DCP-3500 will go straight to the DT. So flow rate can be what ever.
Pump (what size?) - in section one after but with (roller filter, with skimmer) to feed a manifold for reactor, ATS and refugium .. or more a copepod / life rock sanctuary.

So what size returns pipes??...... and RFG? or not? twin returns to 4 x RFG's?
Any good RFG's or waste of $$
No holes for return drilled yet....
Check valves??? - prefer not to...




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The two pumps combine will produce 718 GPH total at zero head. So your actual flow would probably be 50% of that based on what you have said. A typical tank has 5' of head from the sump to the tank. Ever bend, valve and fitting increases head and reduces the flow. Find the flow chart for the pump your planing to use and calculate what your actual head will be. The random flow generators work surprisingly well, but require a fair bit of pressure. I doubt your two pumps ca support 2 each. Especially the one going through the UV.
Most UVs are really bad flow wise with a minimum of 4 90 degree turns as the water flows through them. I just installed a UV and am using one of my drain lines to feed it.
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