Welcome to the forums and good on you for asking on help. But what I notice is you're not hearing what the guys are telling you so far. That, or you are probably a little too overwhelmed to properly process the advice in a planted tank fashion. You're doing a good job of emulating the hardware, but not so much on the harder part yet -- the work involved in getting your tank to where your mind has it. When you're new to this stuff, the right line of thinking might be hard to see and advice sometimes seems conflicting.
So here it is. A site to get your thoughts in order.
3 Growth Pillars - 2 Hr Aquarist
and some special focus here since you're already having algae problems
So, I don't have a 180G tank and I'm sure I'll encounter tons of growing pains if I ever attempt something that big, but I avidly follow journals of small AND big tanks, including your friend @Hendy8888
, and I'd like to think I've picked up a few things along the way.
Knowing what I think I know, one of the early appearing problems you have is that the plants in your tank does not have access to enough nutrients.
Did you read the site about the 3 growth pillars yet? If you do, you'll probably understand more what's being told to you.
told you to think about what you want for this tank. What is your dream? I suspect you want something like @Hendy8888
's tank. In that case, you need to check out his journal. It looks amazing just from the pictures, but if you read a little deeper, there's a wealth of information to be had. Here, he's encountering algae struggles : https://www.plantedtank.net/forums/1...l#post11127955
and more https://www.plantedtank.net/forums/1...l#post11144249
. But focus on what he does each time to get out of it. Hard work. Maintenance. Course Corrections. I'm jumping through his journal but you might want to find some time and go through a little more thoroughly. More importantly out of all this, look at his dosing schedule. https://www.plantedtank.net/forums/1...l#post11164575
. He doses more than you do DAILY. In a 90 gallon. This is what Greggz meant when he gave you the chart showing your thrive dose. Thrive is not a bad fertilizer, but not dosing enough is 'bad' in your situation. What is enough? Heh, that's part of the hard work. Guys like Greggz and @burr740
is still trying to figure it out and they've GOT amazing tanks. But lemme not scare ya. They're "nitpicking." @AguaScape
probably hit the nail. Generally, you've got not enough of the basic nutrients to begin with -- whether it's a micro or a macro. Plant issues and algae is telling you that. Especially as you've pointed out, the plants not in soil are suffering. OR, it could be like @OVT
said, something is off with your water to start with and you're missing those nutrients. No dosing = no nutrients = no food for those not in soil.
Also, note how Hendy8888 is pushing his CO2. There's more than one post where he's tweaking it higher (safely). These guys are really pushing and really studying everything, and if you want a high tech tank that amazing looking, this is the reality underneath the gloss.
Your six tests is not all that it takes for a high tech tank. And yes, some people can get by without testing, but it takes a real trained eye to not have to test. So if you read that, don't give yourself that out.
is right. Your tank is hardly 'fully' planted. It might be dense in sections and with enough reading, you'll soon realize maybe too dense is not good either. But 'fully planted' is a slightly different idea. Going through the 2hr aquarist's site and journals of Greggz, Burr, and those guys, you can see what is 'full'. Even Hendy's is covered majorly with a carpet.
Read the 3 pillars yet? Go read em.
So, barring the green water bloom, nutrient reduction is not something you want to do. Definitely not long term. Light reduction, yes. for now. I suspect that's the right move. More light drives plants to run out of the little food that you're providing and sort of fizz out. Thusly, reducing light creates less demand so that your plants can get healthy faster. Get your plants healthy before chasing reds from rotala macrandra. True, a non red macrandra might mean not enough light, but better have it survive and figure out other things first before chasing that one plant that will be the downfall of your entire tank.
Stick with less light,
add in regular maintenance -- probably at least weekly water changes right now as your tank is upset so water change your way out of trouble,
revisit your water as others have suggested -- realize that your water softener strips out stuff as OVT and houstonreef mentioned -- now you may have to re-add those specific nutrients,
nutrients -- figure out to increase thrive (ask the creator: nilocg) or start out with EI,
THEN just 'think' about increasing lights.
Think long and hard before you rock that boat.
When you're plants are healthy and your algae is in check, THEN, you go back and slowly increase your lights. At least the way I'd tackle it. But what do I know.. probably I just know how to write something persuasive sounding
Wait, your dream is a low tech tank? Oh, then maybe you can relax on your upkeep. If you're not ready for the hard work and like your tank to run on cruise control, then go over to the low tech forums and see what's possible there. If you're okay with that look, then by all means, you can have a successful tank that way too! Light reduction is definitely the major component of their designs so again, you've done good there.
Are you still only one month in? Are there any observable new plant growth to brighten your hopes? Perhaps a good dose of patience is needed too. Do a lot of reading, follow journals -- start with the guys who posted before me and burr740s -- they've got good ones, create your own journal, keep soliciting help, but more importantly, listening to that help! Pick up good habits and your dream is within reach!