Regarding the flow rate of the filter, I have explained this in detail previously, you can check this out:
viewtopic.php?f=33&t=673193 過濾
.......
要留意濾桶流量的廠方 rating 多是以空桶和零揚程計算,所以當你塞滿濾材然後將水谷上離濾桶一米高的缸頂,實際濾桶流量可能一半都無。行了幾個月後,濾桶內積聚大量污物,進一步減 D 流量,到時可能連 1/3 的廠方 rating 都 keep 唔到。另摩打好力與否同摩打的 capacity 是兩樣不同的特性。我們形容摩打好力通常是指高扭力。所以1000L/hr 同 1200L/hr 無乜分別,但 Eheim 1000L/hr 一定好力過大陸 1200L/hr!要留意揚程等數據和你實際使用時所需揚程的流量。高揚程多數係高扭力,亦即所謂較好力的摩打。若因流量過大出現打大風一D都唔難處理,將雨淋管的孔改大,或將出水口向上或缸邊或甚至加出水口分流也可。
On top of the 揚程 issue, the path of the circulation also will slow down the circulation. When you add more 轉角位 into the circulation path, the flow rate will reduce. Therefore if you include a chiller into the water circulation path (which you have to), then you have to expect further lost in ACTUAL circulation.
If you really cannot use two filter, then go for the Eheim 2078 or the Classic 2260. To be honest, I personally prefer the Clasic 2260 over the Eheim 2078. 2078 is more "convenient" but 2260 is more powerful in terms of filtration efficiency. If you can install two filter, then add 2217 or 2208 into your system and that will definitely work better. Two is better then one in my experience, you can stop one filter for cleaning and don't have to worry that the aquarium has no circulation during the cleaning time, even using a small 2217, this will allow you to remove the main filter from your tank for 1 day, and you can really clean up the filter without worrying that the N cycle will be damaged significantly.
For the chiller, I use TR20 right now, so I am familiar with the 日生,海利 and Teco products, but if I must recommend a Artica, I would say 075 is the lowest possible model according to the data sheet you provided.