Pump sizing help for inline chiller

[Rails]

Just got an inline chiller teclima micro used off ebay. Its working great by the way, will post a review after more time goes by. My issue now is getting a pump that doesn't chatter like crazy pushing the water.

Manufact recommends 2 to 3 min per gallon flow through or 120 to 180 gph. My research on head height, etc led me to believe I needed a much larger pump.

Here is the setup, the powerhead or pump is in the aquarium. It pumps water up and out through 1/2 id tubing, down about 5 feet of hose and up about 6 feet of hose. The articles online said the down hose takes off about 1/2 the head height of the up hose b/c of gravity, so I figured 3 ft of head. There are 4 90 degree elbows, so I figured another 2 ft of head.

Tried a Rio 600 I had around and it seemed to chatter pretty loud. Then got a CAP 800 at the recommendation of the LFS. Seems to work OK, but it chatters like its at the edge of its max head.

I'm wondering if anyone has one of the smaller inline chillers and what pumb powerhead they are using.

[Doug1]

How bout a MAg5 or even a Sen 700 iwth small tubing and bends it should be ok , its a semi pressure rated pump