Some back history.
My first real try at a "planted tank" was my 33 gallon. The tank had very low light (40 watts of T8's at about 24 inch depth). The tank started off relatively well, I was dosing Flourish and using Osmocote caps. Plants were scraggly at the bottoms from the low light, but still growing. And then all of a sudden I got a ton of algae - I could handle the green dust and the BBA, but then there was cyano... it was vicious and FAST spreading. Within days my entire tank would be coated. I tried adding a powerhead for circulation, dosing KNO3, spot treating with Excel and H2O2, leaving my lights off for longer periods of time, adding DIY CO2.. I even did a full blackout, multiple tank drains, plant dips, etc.. but it came back with a vengeance every single time. I eventually took down and sold the tank because the cyano was so bad it was choking out my plants. My fish got some horrible disease (NTD? TB? Who knows) and the general population was completely wiped out. I considered giving up at this point, but I decided to try high tech, since I was employed at the time.
In its peak... there was some algae (especially on the slow growers like the anubias) but at least things were GROWING.
Then the cyano hit...
Fast forward to today. My tank now is the following
ADA 60-P (17 gallons)
Aqua Soil Amazonia New
Eheim Ecco 2234 canister filter
12 Cree XPG's on a dimmer with the amperage turned way down, like 20" above my tank, 8 hrs a day
Temp's around 76
I dose CSM+B, KNO3, and Seachem Potassium/Iron according to EI light, twice a week (I also have K2SO4 but I am too scared to dose this with my relatively high GH/algae issues)
I do weekly 20% WC's
Tank's fairly lightly planted because NOTHING IS GROWING. Stocked with 4 adult guppies and ??? fry.
I have a CO2 cylinder and regulator but the reg broke on me and I don't know when I can get it fixed. I planned on going high tech with this setup, hence the lights. But I have turned them down... way down. Down enough that they should qualify as happy low light. As far as I know, I'm doing almost everything right with this tank. But I'm still getting CYANO and NOTHING IS GROWING. It's like I'm cursed with this blue green sludge. No matter what I do, it comes back. I have tried everything apart from antibiotics and I would prefer to not go that route unless it absolutely comes to it. I was under the impression that once I got the environment stable (good circulation, decent nitrates, good plant growth etc) that the cyano would resolve itself in time but it's just not. I think it's gone, and then 3 days later I can see it starting to creep over my AS, taunting me. Here's how it looked before I turned the lighting down:
And here's how it looked 7 days later after TWO massive cleanups:
As you can see there's been very little plant growth (especially the rotala) and the HC carpet completely died (I kind of expected it to in a low tech environment). But between that photo and today the cyano has come back once more and is starting to spread over my substrate once again. I even added more plants - some vals, bacopa, and some c. parva.
The cyano, creeping back up on me...
And my 4 fat, happy guppies (and some hard water stains - my tanks evaporate FAST with all the heaters running!)
Okay, now that I've gotten that out of the way... what should I try next? Why am I cursed with this stuff? Do I just need to boot it with antibiotics and be rid of it? Why did it happen in the first place and why can't I seem to get rid of it without using antibiotics? WHY IS NOTHING IN MY TANK GROWING?
Grrrrrrrr.... I just want to look at this tank and cry. I've invested over a thousand dollars into it, countless hours and research, and even more hours with my hands in there trying to make this right... and I've been nothing but a miserable failure. I can't even figure low tech out. How do you guys do this? How come some people can just stick plants in dirt and have a beautiful tank? I'm cursed.... I swear.