Chiller flow through advice

[Neaco]

Just connected a chiller to my 120 galllon reef tank.  Flow rate in the manual for the chiller says 480/2400gph.    I have a mag 9.5 pump (1010 gph at 1 foot) going directly from my sump to the chiller then back out into a Y connector and then into two directional U tubes hanging on both sides of the back of the tank.  I measured my flow rate out of each directional U tube which was equivalent and the combined output (adding both tubes) was 190 gph (3/4 inch inner diameter tubing).

 

This is reducing my tank heat sufficiently at this point.  
 

As long as this is reducing my tank heat sufficiently, am I good to go?

 

Will this in some way cause problems or decrease the life of the chiller because not enough flow is going through as recommended?

 

If I get a pump that has double the output, (say a Mag 24 2400 gph at 1 foot), will this truly double the output from the chiller or are there “flow dynamics” with the Y connector and U tubes that would prevent doubling the output?   I would hate to get the mag 24 pump and find  out that it only increases it by 50%.  Any thoughts greatly appreciated.  
 

[Neaco]

Finally got through to JBJ Aquarium who makes the chiller and said it would be overworked if not at the minimal flow.  So have the same question about the pump.   

[Neaco]

Ugh.  Got a 2400gph Mag drive pump.  As I feared.   The pump that is 2.5 times stronger than my Mag 950 gph pump only increased flow by 50%. 

[DaJMasta]

Do you know what the ratings for the chiller are?  Is that GPH for different target temperatures?

 

Provided the chiller has the same duty cycle, there shouldn't be a substantial difference in performance between flow rates.  Chillers will just cycle on and off as required to hit their thermostat goals, and provided you have enough flow through it to keep it from chilling the water around the sensor to the point of shutting off the chiller when there's still work to be done, the heat removed shouldn't be all that different in low but still to rating to moderate flow.  There's likely an efficiency bonus to a higher temperature differential, so higher flow may be somewhat higher efficiency, but this will always drop as you approach your target temperature, so that's really only a factor after it's first switched on or if the chiller can't keep up with the target temperature.