I do think that this lack of luster and shine all boils down to two basic things, the purity of the materials which translate to "usable food for plants" and water chemistry.
We know the inputs are there because we add them to the water in our nutrient formulas. BUT, for some reason (water chemistry) they are not getting translated into available nutrition for the plants.
One way to test this is to use ONLY pure materials in your formula that require no "translations" if you will to be "plant available".
After you establish a pure formula, then you begin to methodically adjust the ratio and concentration levels according to plant health until your desired goal or target is reached.
It was very hard to find a formula that contained only pure inputs but we managed to find 2........maybe. Well one for sure (Shiva).
Shiva 2 part from Crop Nutrients was the cheapest and better route to take IMO and if you look at the ratios it is more concentrated than any other brand which means you use so much less. Optimal PPM levels are like 300 to 400PPM on a .5 (x500) conversion scale. They use only pharmacy grade materials.
At first glance this stuff seems way expensive but once you see how little you need to use of it due to its purity and how it eliminates the need for a lot of expensive additives, you begin to see that is not only the purest and most stable but the most cost effective as well. You really do have to try this stuff to understand the purity levels used in the formula. It contains "Natural" ph stabilizers.
Veg+Bloom by Hydroponic-Research was the 2nd but it is more costly as you have to get a custom formula made (ammonia free) and there is a minimum to purchase which is 10lbs of a one part powder formula you use from start to finish. For larger systems dealing with a powder can be a problem or cause extra work and space.
To be honest getting that luster and shine back with this powder was a bit tricky to do and required lots more testing and trials to "dial in" the formula. I also question some of the inputs that are not listed and kept "secret".
The way the formula is designed to work is that at up to about 600PPM it acts as a veg formula and then at 800PPM it acts as a bloom formula with PK boosters. The problem is that different type plants require different nutrient levels and 600PPM for one plant did not translate to a proper veg formula, this could also happen with the higher PPM levels as well and then your back to dull looking plants that just look like they are "missing" something. And this is because they ARE!
You can get there using this one part powder though, just be prepared to spend some time on details in tweaking the formula.
One great thing is that this company will take a water sample of your water and custom make a formula for you. Very nice service!
We found by using only pure inputs at the right ratio's was the only way to get that luster and shine back and keep it back from start to finish.