Yes, Seiryu stone alters water parameters. I have some in my tank, but they are small stones that were sold for a nano tank ( I have a 40 breeder) so they haven't caused problems. Since you knew these stones were causing a problem, why did you keep them? Keeping for the sake of not having to dose calcium while they are reeking havoc on the rest of your water parameters is not a good idea. It is easy enough to remineralize RO water and for a small tank, it will cost next to nothing to do so. Planted tanks like stability.
As for the green spot algae, this isn't always a phosphate problem. If you have high organics in your tank from dying plants, that too can cause green spot.
While it is true that plants melt and go through awkward phases as they adjust to new environment, sick plants are algae magnets. Mosses in general tend to be algae magnets because they collect stuff that is floating around in the water column. Vacuuming them or using a soft toothbrush to remove the detritus they collect once a week during a water change keeps them algae free. Some mosses also need to be trimmed as the base layer will die off without light which causes more problems with organics in the water column.
What does your tank maintenance schedule look like?
As for EI itself, I'm not willing to go into that rabbithole, but I will say that it is meant to be modified. My bottle of orange water from Tropica is also EI, but it doesn't contain nitrates or phosphorus. I don't dose my tank what Tropica recommends as I don't use CO2, I don't have stems to feed and my fast growers Vals and Giant Hairgrass are given root tabs which contains some phosphates, but most of the phosphates in my tank comes from fish food.
There is no true definition of 'heavily planted', but usually that means more than 75% of a persons' tank is covered with plant mass. Your tank does not meet that so-called standard.
Seiryu - ita not cuasing problems anymore now that I do more water changes throughout the week.
Green spot and maintenance - Water change used to be 30% a week but now it's definitely 50%. I scrub the glass clean as well but explicitly didn't scrub the tank for my pictures so people could see what it's like at the end of one week cycle.
Amazonian sucks up PO4, among other things.
10 ppm NO3 and 1 PO4 my tank would crash.
60 PAR is on the low side for fast growing flowery stems. And light spread/PAR drops off quickly off center with LED's. PAR at edges might be significantly lower.
CO2 still seems on the low side.
BBA usually related to high organics, not enough maintenance, and unhappy plants
I would find journals of tanks you want to emulate that started up with Amazonian.
PAR has shown it can grow plants just fine so I'm not sure it's that.
I can turn up my co2 but it's already near the point where it makes my fish grasp. My puffer will start gasping when he starts running around chasing bloodworms.
As you saw, TDS was o ly 257 and I'm doing at least 50% water changes each week to keep the calcium at 50ppm and gh at 8.
I'll have to check out journals that use this substrate. I thought amazonia was the too tier substrate that everyone wanted to use.
If you want to eliminate that it's EI dosing just use some K and micros for the next few months and see what happens. Every tank I started with aquasoil that's all I did for the 1st 6 months and everything started up clean. Granted all tanks are different but the AS is so loaded that you don't really need much else in the beginning.
If your getting BBA that quickly to me that's an organic / light / co2 imbalance.
So I had stopped dosing everything except co2 out of frustration and what you're seeing is what happened. Holes came back and lower leaves died within a week. Before, I had to dose 4-5x phosphate and potassium to get the tank to bubble.
I thought me overdosing compared to EI was way off, but from what people are able to tell me so far in this thread (basically nothing, sadly except I have calcium rocks and aquasoil) the extra dosing may have been warranted.