Let the blue remain as it is? What you set your WB?Adjusting white balance helps to a certain degree, but if you have your lights set to 100% blue, your photos will still have a blueish hue even with white balance set as high as it can go on the camera. Ideally you should set the white balance on the camera in conjunction with adjusting the aquarium light spectrum if possible. I have Radions and just turn up the white channels a bit when shooting photos.