I’ll try my best to touch on everything here.
Maybe I should turn it on in the AM so they could feed him in the morning, then shut it off a couple hours later as they'll both be in school. Then turn it back on right before they get out of school. Would this be ok to do?
It’s not ideal, but it’s better than running it all day. I would make it more uniform though, like 6-10am on, 10am-12pm off, 12-4pm on.
My Nitrates always tend to be in the 20-40 ppm range... I think. I can never really tell if it's in the 10-20 or 20-40 ppm range based on my API test kit color chart. I don't have a Phosphate tester, so I'm not sure where that is at. Is this a must have? If so, I'll pick one up.
You can just buy an API Phosphate test kit, no need for some fancy digital tester (I don’t even know if anything like this exists for the hobbyist level)
Just yesterday, I ordered a bottle of the NilocG Thrive from their website. Are you saying if my Nitrates and Phosphates are fine and say I add Seachem Potassium, I won't need the Thrive? Would it then be overkill? Does the Thrive provide Co2?
I would test your phosphates first. You don’t have a ton of plants, so if you can get away with just adding Potassium and Micros, that would probably be preferred. Please note, this is not a reflection of the products NiloCG sells; they’re very good and cost effective. I just doubt that you need very much in the way of nutrients with such a light plant load.
In regards to the Flourish Excel, if I don't use it, would I not be depriving the other plants from Co2? Is there an alternative?
First off, Excel is not liquid CO2. Excel is a carbon substitute that plants can use, but not nearly as effectively as actual CO2. Most of the community actually use it for its algae killing abilities more than as a carbon source. With that out of the way, your plants will do fine without it as long as your lighting isn’t very intense or for too long of a period. Once you start getting into higher light and more demanding plants, CO2 is needed to help the plants grown and prevent algae. As far as an alternative, the only thing besides actual CO2 is Gluteraldehide (Excel). I personally use Metricide14 instead of excel, only because it’s really the same thing, only cheaper. Any Glut products are going to have the same impact on your Vals.