I'm not, I've just fiddled with the other stuff already and I'm moving on one thing at a time until I find an answer. I'm trying to give as much info as possible
Sorry I haven't answered all the questions you might have before you asked them, but honestly your condescending tone isn't really helpful either.
I apologize if you felt that way. I certainly had no intention of being condescending. There is something in the hobby called "nutrient tunnel vision". It's basically that many think that fert dosing is the cause of and the solution to all problems. It's not. IMO, a holistic approach is much better. That is looking at the tank in it's entirely. Takes more effort, but in the end usually provides much better results and solutions.
My pH out of the tap is 7.5. Tank water is at 6.6 before CO2 is on. After CO2 is on it drops to about 6.2. Tank is much lower than tap mostly because of ADA aquasoil I think. Drop checker is green when CO2 is off, and limegreen when it is on. CO2 is just about as high as it can be before shrimp start to react to it negatively.
Now there is some good information. You have got fresh Aquasoil. And yes, it will lower KH and also suck up PO4. Now this is not meant to be condescending either, but how are you measuring pH drop? Liquid test/strips/calibrated pH probe? Your drop from 6.6 to 6.2 doesn't seem like much, but if the drop checker is being used properly and shows lime green then I agree CO2 should be fine. But again, I had to ask above as BPS is not a reliable or accurate measure of CO2 injection, and that's all the information you had provided at the time.
Unfortunately the LED tubes didn't come with a PAR rating and neither did I find anything online, so I asked the customer support. They claimed the lights were "+220 PAR at 20cm". When I asked if they had data at more common depths, they said that is all the info they had. The lights are bright and have no dimming function, so they go at full blast for the whole 8 hours they are on.
What exact brand of LED's are they? Maybe someone has experience with them and can offer help. The reason I asked is that both too little and too much light can be a problem. Too much as it promotes algae, and too little as plants may not be getting enough to be in peak health.
And light needs to matched to your plants. I didn't notice you had a link to pics before, but had chance to see the tank now. In the future, it's better to learn how to include the pics in the post.
I see you have a mix of high and low light plants. Anubias, Swords, Mosses, what looks like a Buce or crypt, and then some ground cover and stems. Somewhat tricky combination as some would like very low light, and then some would like much higher light. And all in all, IMO the tank looks pretty darn good for only being a little over 3 months old. A lot more going right there than wrong.
My goals are to get my tank to prosper without algae. You'll find pictures in the previous post, along with a gif that shows growth in a recent 10 day period. Plant growth is good and healthy, but unfortunately so is algae growth.
I don't know what you mean by optimizing maintenance, but I get my sleeves wet once a week and have done so since setting the aquarium up. I've tried optimizing CO2 and I think it is as high as I can have it without dangering livestock. Light cannot be controlled and getting a dimmable light is a 500€ investment so I am looking at other options first (changing parameters I can affect). If there are no alternatives, I'll have to save up and buy the dimmable light.
Well you are not alone there, it's everyone's goal to have a tank prosper without algae. Takes some time and trial and error to make that happen. Your tank is still young and some algae like I see there is to be expected. When I first got started in the hobby, somebody told me it may take a year to get a tank truly in balance. I laughed....but turns out I was naive.
Maintenance includes large regular water changes, removal of any dead/decaying/algae infest leaves. Plant mass management with regular pruning/trimming. Also includes keeping filters clean, substrate vacuumed, limiting fish feeding, and in general keeping uber clean conditions and low dissolved organics in the system.
And keep in mind my point about focusing on ferts is that very few algae problems are fert related, unless you don't have enough. Most is the result of too high of light in relation to plant selection and too many dissolved organics in the system.
The biggest thing that struck me with your post is that you have a young tank with ADA Aquasoil. If I were you, I would seek out tanks that use Aquasoil, and learn more about how they managed the start up of the tank. You may not need to be dosing hardly any ferts at all right now with an active substrate.
I have no personal experience with it, so can't be of much help. @Asteroid
above has experience with starting up tanks with Aquasoil and may be able to offer some insight.
And my apologies, I certainly did not mean to be offensive at all. Good luck and look forward to seeing how things go from here.