Gotta love a tank with rainbows :-)
Something that occurred to me early on - when using Rotala butterfly I learned it makes a difference how much water you list in the formula. A 55g tank likely does not have 55 gallons of water - even when you add the volume of the canister filter. For some of the crazy high tech, high light, high needs tanks it really does not matter as much. In your case, being a tank with much lower fert needs it can make a more significant difference.
The Fluval 3.0 light is nice as you can adjust the lighting levels (PAR) down to most any level that you could need. With a 12" wide tank, a single light should be enough.
Your plant list does not scream "high needs" to me so I would definitely go with the low light/weekly dosing for macros. Micros can generally be run pretty lean as well, especially seeing the CSM+b levels for EI seemed a little too high in the opinion of many.
"Kh 4, Gh 7, PH 7.6, Tds 245, Temp 76, Nitrate is 2-5 before ferts" are some pretty good tap water numbers. Most would be happy with them.
KNO3 2.8 grams, divided by 2 = 1.4 grams 2 x weekly for nutrient consistency (10ppm weekly)
KH2P04 = 244 milligrams which is 0.244 grams divided by 2 = 0.122 grams 2x weekly for nutrient consistency (1ppm weekly)(about 7ppm weekly K)
(most of us would say we are dosing a weekly NPK of 10/1/7)
The above seems about right. There is some debate about running the PO4 closer to 5ppm vs 1ppm weekly. I am in the 5ppm group. The interesting part of your situation, with not dosing K2SO4, I would think you might run short on K. But, the reality is the plants will tell you if that is the case (pin holes with yellow edges in your crypts and swords).
Your CSM+B numbers above match up to what I am seeing on Rotala Butterfly. Comparing the individual weekly ppm's to what I does, they seem pretty low. Again, my tank is a very different animal.
I would give your newly listed fert numbers a try and see how things work out. Also remember, patience in this hobby is the most difficult part. I may take a month or 2 of consistent dosing before you can say it worked or didn't work.
Recommendations would be making a liquid micro mixture as opposed to dry dosing. Also, if you are having some algae issues, try less daily light power and/or higher KH2PO4 dosing.
More good info - https://www.plantedtank.net/forums/1...ng-thread.html