skipping ahead here (have yet to finish reading all the posts on this thread)
... so maybe this is already covered.
but, here goes ...
you don't dose regularly
you don't want to use dirt
where exactly are your plants going to get their nutrients from ?
you don't have any nutrients in the substrate (no dirt) and you aren't adding any to the water ?
... and you want excellent growth ???
am i getting that right ???
personally i would avoid root tabs, (high nutrients in one area of the substrate and low in other parts)
also, personally, i am in favor of dirt.
dirt i am looking into alternatives over what is marketed though
(technical problems relating to nutrient cycles in the substrate with a personal interest that requires a higher degree of knowledge over the common hobby interests - "self-sustaining")
problems and fears of dirt are about nutrients being cycled, a very natural process as detritus is broken down into it's finer components. in (i forget the terms at the moment) higher oxygen content substrate (upper layers) various nutrients are released so plant can use them, but not all nutrients. some nutrients are only made available in the lower oxygen deprived layers.
the production of toxic gasses i hear people worry about are a natural process, these are also produced far enough away from the water column to be "safe", and are released into the water column from slow diffusion, where they are rather reactive with available oxygen and rendered safe.
i put "safe" in quotes as - everything is very safe provided YOU do not disturb the substrate, which would bring these toxic chemicals directly into the water column in abundance instead of naturally in tiny quantities which would be rendered safe for all tank inhabitants.
if you are concerned about any of this, it's not a concern of dirt or not, as over time detritus WILL fall into the substrate.
regular maintenance will not clean it thoroughly enough. i have seen a thread on another forum, what was vacuumed clean (with fish removed) was then stirred up by hand and visibility was reduced to a few inches only.
you can reduce the effects of detritus build-up, but you will always have some in there.
please reconsider how you are taking care of your tank plants
if you have algae. i would make a few recommendations
1) ignore it, sounds backwards do it anyway. focus on your plants, healthy plants will out-compete your algae, if you don't have healthy plants you will have algae
2) identify your algae, find a critter that will eat it.
2a) i would recommend the nerite snail, eats about all algae, does not reproduce in freshwater.
note of caution on the nerite snail, they will eagerly climb out of the tank, where death may become an issue as they are still an aquatic snail.
now back to reading