Am I on the right track? And how to dose CA(NO3)2

Hi all, Is this the right forum for this post? I wasn't sure.

First off, I know this is a looooong post. I feel that giving too much info, is better than too little.

I am so excited to at long last begin taking the plant side of aquariums seriously. I have kept tanks at a few different times in my past. As with most things nowadays, the information explosion makes it easier to do things better, but at the same time, sifting through everything can be overwhelming.
Thats where forums come in!

I want to know if I am on the right track in general, and I have a few specific questions too. I am technically inclined, especially in the area of chemistry, but as I said, this is a new area I’m getting into so please excuse my ignorance, and don’t hesitate to pick my strategy, described below, apart.

My goal is to keep a low-light (reasonably lit) tank with DIY CO2. I want the plants to look good, and since its a hobby, I like the maintenance aspect, so I don’t mind trimming, tweaking, etc.

My Tank
75G. Rema XP3 filter. Magnum HOT 250 filter. Gravel substrate. 34W T8 5000K + 68W T8 6500K.
Lights run for 10 hrs a day. 2 Air bubblers running from lights out to 2 hours before lights on.
DIY CO2 currently with 2 x 2L bottles running, a third bottle to be added in a weeks time. The DIY CO2 and 64W lights were added about a week ago. CO2 diffusion is via the inlet of the HOT filter which seems to do a fair job of chopping the bubbles up, but the spray of bubbles that comes out is in spurts.
My spraybay from the XP3 is divided: 1 bar runs from the top left of the tank directed against the glass. The other runs along the back of the tank bottom, directed toward the front. Since its a big spraybar, with many holes, flow is gentle with not much plant movement, and almost no surface movement. Today, I will be directing the left spraybar into the tank (L to R) pointing slightly down from the horizontal, and the bottom spraybar about 60 degrees up to see if I can get better flow across my plants without creating a major surface disturbance (I do have, and want some more, floating plants).

My Plants
A couple of bunches of Riccia – floating. Java Fern – about 10 plants attached to fake wood. Java Moss – about 5 clumps attached to fake rock. Vals – about 6 plants. Cabomba – about 6 stems in two or three groups. Rotala – about 6 stems in two groups. Crypt willissii – about 8 plants. Recently added a large Amazon Sword.

My Fish
Not a full list, but mostly corys and rainbowfish, and a few loaches, dwarf cichlids, rasboras. I think the point is that it is well stocked community tank. Possible slightly overstocked.

Current Issues
Plants are growing, originally slowly but faster now that I have CO2, excel and micro ferts being added over the past couple of weeks.
Shortly after the tank cycled there was some brown algae (diatoms) growing on the rock, and I think on the Java Moss and Java Fern too. This seems to have slowed, perhaps stopped, but isn’t reversing. Difficult to say what kind of algae since I’m not good at identifying algae. The Fern has some older brown leaves which have developed a bit of brown stringy fuzziness. Newer shoots are a bright green. The older Moss growth was also brown but the newer growth is a lovely green.
The crypts have some older leaves which are partly off colour – almost look melted but I don’t think they are. There is some stringy algae growing on them too.
Some of the Vals melted a bit, but the smaller shoots seem good (I've read that Excel does this to Vals).

My Dosing Strategy (Current)
5mL Excel (actually the API CO2) daily. Increased recently from 7mL every second day.
7mL Seachem Flourish Comprehensive twice a week (used to be once per week).
DIY CO2 – 3 bottles, 1 replenished each week. Currntly using bakers yeast, waiting for my order of champagne yeast to arrive.

My Dosing Strategy (Future - waiting for ferts to arrive)
Estimative Index NPK/CSM+B using Ca(NO3)2 instead of KNO3 (only because its difficult to get KNO3 in Canada)
Osmocote root caps in vicinity of Vals, Crypts and Amazon Sword.
DIY CO2 – 3 bottles, 1 replenished each week (+5mL Excel every day???)

Specific Questions
1)What to do with the Riccia. I kinda like it floating, but are there better options?
2)Should I trim away some of the brown fuzzy older leaves from the Fern?
3)Should the tank be showing visable current (plant sway) without breaking of the surface?
4)Since I only have DIY CO2 (3 bottles) in a 75g tank, should I continue with 5mL Excel dosage every day?
5)I'm aware that Ca(NO3)2 offers more NO3 per gram than KNO3, and I can easily adjust the quantity based upon molar mass. What I’m uncertain of is that since part of the K dose has now been replaced with Ca, should I increase the K2SO4 dose to compensate (again using molar mass to calculate), and will this mean that I’ll have too much sulphate?
6)If I premix the macro nutrients into a stock solution, wont CaSO4 precipitate out when mixing Ca(NO3)2 with K2SO4 because of the limited solubility of CaSO4? Does this mean that I should not premix a stock solution of these macros?
7)Is there a EI calculator available that works with Ca(NO3)2 instead of KNO3?

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