Hi Kingy,
OK, thanks for the photos. There appears to be a couple types of diatomic algae typical of newly setup tanks.
Theoretically, the algae should go away by itself after 2-3 weeks, however, the situation is often exacerbated when we make mistakes, such as having too much light and/or if the flow and distribution of flow are less than excellent. If these faults are egregious then the diatoms do not go away and instead become a plague.
It's difficult to determine if there is excessive lighting without the proper tool, such as a PAR meter, or without information from the manufacturer, so if possible, it's often a good idea to reduce the intensity of the lamp to provide a margin of error.
One also has to verify whether flow is actually good, as well as if that flow is being distributed properly. I can see, in photo #4 that there is a single pump outlet pointing along the length of the tank, a configuration that I'm always suspicious of. I don't know the size of the tank or the rated flow of the filter so it's difficult to assess.
There is also the issue of what the injection rate is and when does the light turn on in relation to the behavior of the gas.
The timing of the CO2 is very important. I can see the DC is a dark green, which is a bad omen. It should be a nice light lime green when the light goes on.
You can do frequent large water changes and use a toothbrush to pull out the strands as often as possible, dosing the nutrients after each water change. On the plants that have broader, thicker leaves, such as the Althernantera you can use your thumb and index finger to scrub the leaves and remove the dirty looking film from the leaf surface. That helps quite a bit.
Cheers,