First question I asked was about how to monitor coolant temp in the hybrid AIO (my brother has a 3080 FTW3U Hybrid). From what I could gather, you can't. If someone can still correct me, please tell me where I can find the coolant temp. Been using Precision X1 to see if it is there but we couldn't find it.
Second question was regarding my loop in my system. I have a 9900k and a 3090 in a Corsair 500D RGB SE case using Hydro X parts (360 front rad as intake, 240 top rad as exhaust, DDC pump and five LL120 fans - specs in my mod rigs profile). With that setup using thermal probes on the Commander Pro, I was seeing coolant temp at 53C and climbing with case internal at 39C and ambient temp at 28C. Basically my system was a hotbox. Comparing temps against other users with similar cooling setup and similar heat output (~450W), they are posting loop temps 10-15C below mine at a lower RPM (my system was ~80% RPM which is 1500 for fans and 3500 for pump, they were running 1300RPM fans with the exact same fans and 3000RPM on the same pump with much lower temps). If that was all, I wouldn't really care as I'm not a snob for temps, but I read that DDC and D5 pumps have a max operating temp of 60C. My loop temp was still climbing with no leveling off. Slowly but surely I believe it would creep up to 60C, so I had to do something.
Just for reference, I found that most users agree that loop temp at under 10C above ambient is great, 10-15C above ambient still good, anything above 15C is bad and above 20C is problem. I was at +25C.
Well, I found out that front rad intake and top rad exhaust for mid towers are only for show builds on youtube and Corsair's advertising (which is misleading and upsetting as it caused me to rebuild this system more than once). Unless you have better fans or better air flow, most of the heat that is trapped in the case will slowly warm up the loop. While I wanted to purchase another case and better fans, I found out that simply flipping the fans on my front rad to exhaust and causing the negative pressure to draw air in through the open rear exhaust would mostly solve my problem. Kinda against the whole "air flow" chart you see on Corsair's case page. But also if you use Corsair's "design your own loop" and check out their build guide pdf, it actually shows all of their mid-towers as setting all rads to exhaust and allowing air to be drawn in through the rear of the case. Doing this cause my case temp to stop climbing at just over 5C ambient (instead of the previous +11C) and loop temp to max out at 43C (+15C over ambient). Still not the best result, but I'm okay with that for now until I upgrade the entire system a few years down the line.
So now I have a nice black radiator staring at me if I look at the front glass panel. Kinda defeats the purpose but I never planned on water cooling with this case when I first purchased it (it was pretty passable for hybrid cooling at least). So I rotated the case a bit so I don't see the front anymore.
I guess if anyone else wants to water cool in a case like this, don't do what I did unless you have much better high static pressure fans. Sorry if the post was a bit salty, but you could probably tell that I'm upset over misleading case advertising. Yes, custom loops are still a tiny part of the market, but as they are pushing their own brand of custom loop parts, a bit more honesty when it comes to their cases would be appreciated.