4 t5 bulbs in a 40g is way to much. that is the main problem for algae growing on the glass and plants. if u want to keep this light ur gonna need a lot more plants to compete with algae. no amount of oto will fix the algae problems. with your light its consider high tech. with that light u will need tons of plants and fertz co2 to balance out the tank. or u need to take out 2 bulbs to cut the light down. the plants u have in there are easy to grow low light plants u dont need that much light. so u either have to cut back the light OR get a ton more plants to compete with algae.