Plants adapt to the nutrients they find themselves in. Those in a tank with CO2 adapt to living with CO2, and need it. Those in a high light tank, having CO2 and full fertilizing adapt to that. Those in a non-CO2 tank with little fertilizing adapt to that. So, transferring plants from your CO2, high light 10 gallon tank to the 90 gallon non-CO2 lower light tank, will not allow the plants to just continue the same growth they have been showing. They will likely stop growing for awhile and adapt to the new conditions first.

Just because the 10 gallon tank has a nutrient rich substrate, which I assume Florabase is intended to be, doesn't mean it won't benefit from water column fertilizing too. It might help the plants to start an EI fertilizing program for that tank, even if it is at reduced amounts.

136 watts of HO T5 bulbs on a 90 gallon tank, assuming each bulb has its own reflector, is not low light. It is closer to high light than low light. Add to that, the fact that you aren't dosing nitrates, phosphates or potassium, and I can see how you could be having algae problems. This tank has an inert substrate, so the only nutrients the plants get is fish poop and whatever you dose. I suggest using an EI dosing method here too.