Choosing the Best Flow Pump Speed for my Chiller

[livinlifeinBKK]

Hey guys I have a Hailea 28a chiller but you probably don't know that brand or model so I'll explain...it's a small model that I use for my 10 gallon nano but the 350 liter per hour pump I use is too slow to keep the temperature constant so I'm getting a new pump...the chiller is rated for 250-1250 liters per hour flow so I'm trying to decide between a 500 liter per hour and an 800 liter per hour...which should I go with? I'd say the 800 but a little worried it might blow my sand around since my tank is only 10 gallons so not very deep but do you guys think 500 will get the job done if 350 is leaving too much room for fluctuations? (when I'm in my small apartment I have the A/C on so it cools the water a little and the temp is good but when I'm gone sometimes during the day with the air off I'm worried it's getting a little too hot for the corals I have in there...I'm in Bangkok so it can get pretty toasty during the day

 

[Tcook]

You can split the return into 2 flat fan-shaped nozzles.

 

[livinlifeinBKK]

So

You can split the return into 2 flat fan-shaped nozzles.

You think the 800 would be best, right? That's kinda how I'm leaning and I'll split the return like your saying or just position a rock in the way of the return flow...I need stable temp or my pH will swing along with my temp and stress or kill my corals

 

[Tcook]

You can always throttle back if a pressure pump. What brand and size pump is this?