Help wanted! Bubbles keep forming in my GPU waterblock

[2x R9 290xs in SLI]

Title really says it all . I've been moving the bubble out when the pc is turned off to get rid of it but after a day its reformed in the exact same place. 

I've tried turning the pump to full speed and relieving the pressure in the system.

before putting fluid into the loop I sterilised it using the mayhems blitz kit and cleaned the radiator in the same way using the radiator cleaner .

there are no leaks and temps seem fine .

 

heres some bad photos i took for reference, you can just see the bubble on the bottom left of where the gpu fins are 

 

any help is appreciated . thanks in advance. 

[Hairless Monkey Boy]

Looks like a design flaw with the block, or maybe you are flowing it backwards?

 

In any case, the science is simple. There is a low pressure zone in that location caused by the flow path of the fluid. The pressure is low enough that dissolved gasses in the fluid come out of solution, forming an 'air" bubble.

[2x R9 290xs in SLI]

how do i fix that then ? i know the pump isnt very strong so do i just need a stronger one to provide more pressure ?

[AngryBeaver]

I mean there doesn't appear to be much you can do. Just let the system run it should eventually bleed all of that air out. I mean just because you think all of the air is out doesn't mean it is. I've had larger rads where the fittings had to be on top take several months to finally get out all of the bubbles despite tons of tilting.

[2x R9 290xs in SLI]

47 minutes ago, AngryBeaver said:

I mean there doesn't appear to be much you can do. Just let the system run it should eventually bleed all of that air out. I mean just because you think all of the air is out doesn't mean it is. I've had larger rads where the fittings had to be on top take several months to finally get out all of the bubbles despite tons of tilting.

i did wander if that was the case , ive seen others online saying it was bits of gunk clogged up in the fins but its a new block and i cleaned it all through beforehand and i doubt that it would junk up after onyla  few weeks . thanks for the response