You should be fine, though really what you should do is put more coolant in. I would be aiming your your res to be nearly full.
If thats pre-bottled coolant and you have run out, adding distilled water wont do any harm.
Thank you for the reply. Is the loop run itself ok or any changes i could make?
EDIT: Oh, the PCI-E power I connected, each cable has 2 8-pin connectors. For aesthetics, I connected 1 8-pin to each GPU instead of both the 8-pins of 1 cable to one GPU. Is that ok or do I need to rearrange it so 1 cable powers 1 GPU?