What is Reddit's opinion of Grundfos UPS15-58FC Circulator Pump, Red?

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This is a GPU setup, the parts list for the immersion setup is as follows(minus hoses, connectors, container):

Grundfos UPS15-58C: https://www.amazon.com/gp/product/B07DM3B8HD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

3-row Aluminum Racing Radiator: https://www.amazon.com/gp/product/B08B42W6T3/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

10" Radiator Fan: https://www.amazon.com/gp/product/B00MJO4CRC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

There are 11 total Radeon 580s. The container #1 under the motherboard(the one that's hard to see inside of) houses 6 XFXs, while the other container #2 houses 1 XFX, 2 Sapphires, and 2 Asus.

When operating with both containers, the cards in container #2 heat to 72C-75C each nearly instantly, except for the card with the fluid returning directly on top of it. While operating both containers, none of the cards in container #1 get above 65C.

When operating only container #1, one of the cards will reach 72C+ nearly instantly and continue getting hotter while most of the other cards stay below 68C. If adding the fluid from container #2(allow the pump to cycle that fluid while keeping those cards turned off), the hot cards in container #1 stays around 70C.

I have not yet tried to run only container #2 yet.

I've noticed that many of the cards will overheat without their GPU fans running, leading me to believe the issue here is poor heat transfer from the cards into the fluid, though it could also be a case of poor flow. Does anyone have any recommendations?