You have the rez's so I do not understand that question. If you are keeping the rez's I would not go smaller then 1/3hp. Hot summers I would want a 1/2. JLP artics are nice units,I like aqualogics if you have the money. You need to match the pump with the chiller. JK

they arent attached or connected in any way, hence why im trying to cool them with cool coils, which to my understanding the system would need a chiller with a pump and then a pump pumping the cooled water through the two cool coils no???

Going to need a far size list.

Small Res like 20G with H20 keep it 6.5-7 ph for water to keep clear.
Bigger the Res Less offten the chiller will need to cool it.

Have everything on 1 pump of 600gph. manifold is what i recomend of 1" feed then 1_1/4 return to the res. Off the 1" you have 1/2 shut off to each thing you going to connect to it.

off the 1" place your chiller, both cool coils. then all return on the 1_1/4" line to the small res. The res temp your going to want at 55F.

Fine tuning.... The 1/2 shut off fittings on the supple line will be used. Turn it till the temp you want to Dial in works.

Size of Chiller. Got me, I hear the 1hp make it worth the edison$ or bigger. Oh dont for get to ad a small pump in each res to move the cold around& to mix.

so i guess I'm going to go with a 1/3hp and a 20 gal rez, with 2 cool coils inline.

chiller calls for roughly 250gph pump.

what size should I use on the cool coils?

I would assume somewhere around 300gph as much more would limit the transfer ability due to the lack of contact time

any input anyone????

rez cooling

Hey if trying to cool ur water recommend a aquarium chiller works great don't no if what ur looking for but might help

i had this same question and did not rest until i found it. seems some of these lower HP units arent capable of much cooling with the coils. now as for the resivoir size, the larger(well insulated) the better, upto about half the size of the suggested tank size(example. ecoplus 1/4hp will cool 100 gallon 30 degrees with a 600GPH pump. so build a 40-50 gallon insulated res to help diffuse the heat that comes in from the coils. IE the smaller the res the more the warm water will affect its temperature and the more the chiller will have to work. now that said the max cooling on the ecoplus is 10 degrees of 170 gallons. you need to now account both your res capacities into this and your chilled res. so 150 gallon plus atleast 30gallon(multiply your chilled res size by 1.5 to account for cool coil efficency) for the insulated res. so 195 gallon of cooling. ALWAYS go bigger as these wont peform to their suggested rating most times. so you would want atleast a 1/2 hp, which like he said i would go quiality, active aqua seems to peform the worst for their HP ratings. artica the best, and ecoplus the cheapest with acurate ratings. good luck hope this help. peace