This thread was a great help to me.
http://www.reefcentral.com/forums/sh...on+temp+damage
In regards to higher suction temps, I took the advice of someone that made a lot of sense to me at the time. Check out robthorn's post on page 9 at 06/24/2003 09:09 AM.
There are several good pages of technical stuff around there too.
Check this thread too.
http://www.reefcentral.com/forums/sh...hlight=chiller
The way I see it is, you are overloading your compressor and shortening it's life by subjecting it to greater internal temperatures. Your way may work for a few years, mine may work for 10+. It is hard to tell, but I am playing it safe. I think I am running about 600 gph or less.
By changing my flow through my chiller, I can make my suction temp anywhere from below freezing, to whatever the tank temp is. Right now, my suction temp is aroung 55 degrees and I feel I have a very efficient chiller.
I took my suction temp readings by zip-tieing the remote probe from an indoor/outdoor thermomter to the suction line right before the compressor, and under the insulation. This is still in place today. I did not leave any gage in place.
My system has an orfice, not a TXV, so I cannot give you any real experience with adjusting it. Other than to say, the TXV is better. Get a gate valve before you spend much time adjusting things
You should consult a local HVAC tech with gages to properly set the refrigerant level. The will check the temperature at the compressor suction, and the high and low pressures. These are the minimum requred to calculate what is called "Super Heat". This value should be less than 10.
But.. before you do much else, do yourself a favor and take a few hours to read those two threads.