First some background. The tank has been set-up since around mid-April. At the very start, things were growing like crazy, everything was beautiful. A few weeks in, algae started to take hold and, in retrospect, I wasn't on top of it. I went through stages of just about every type of algae except the dreaded blue-green slime. This was the first aquarium I've had in 10 years, and so there was a learning curve there as well. A few weeks ago, hair algae was just killing me. It had spread over everything and I ended up throwing out at least 50% of my plants (there were quite a few I wasn't wild about anyway). Daily pruning and light maintenence was helping to turn the tide. My normal routine and setup was as follows:
120 gallon (4 x 2 x 2)
6x55 W (330W total) CF lights from AHSupply on for 10 hours per day
Homebrew CO2 reactor made from a filter housing and some CPVC conduit (very proud of this
KH: 4 (add about 1.5 Tbls baking soda at water change to get it up to this)
pH: controlled at 6.6
4x per week:
NO3: 1.5 tsp (about 11 ppm)
PO4: 1/8 tsp (about 1 ppm)
3x per week:
30 ml CSM+B (mixed at 1.5 tsp / 250 ml water)
50% water change on Sunday (sometimes Saturday). I recently started adding K2SO4
Plants were growing good, Swords recovered very quickly from a pretty severe pruning, Elodea growing about 1-2 ft per week. Fish load is light with about a dozen small tetras, 6 Amano shrimp, 2 corys, 4 tiny flying foxes, and 3 or 4 very fat, very secretive Ottos. (I had more fish at one point, but I gassed them with CO2 - remember the learning curve). Basically everything was going good including the hair algae, and I was trying mechanically pester as much as possible.
I had a trip planned to sunny San Diego, CA for 1 week and was scared to death that my recent battles with hair algae would be for naught. So, based on my very, very shakey understanding of the EI dojo, I made the following changes before I left:
50% water change on Tuesday (leaving at 4:30 AM on Wednesday)
Dosed 2.5 tsp KNO3 (19 ppm NO3), 1/4 tsp PO4 (2 ppm), and 2 tsp K2SO4 (for an additional 15 ppm K).
The fish were fed very sparingly with an automatic feeder.
I also dialed the light back to 8 hours of 220 watts, hoping the plants wouldn't motor through the ferts too fast.
I was expecting the worst.
But I came back to a tank that is literally filled solid with plants. Just about every stem plant made it's way to the surface and then some. It's totally and completely overgrown. It looks like the plants grew at least 2x as fast as normal in the span of 1 week. The algae is almost nonexistant. There are a few strands left on the spraybar, but it doesn't look like it made any new inroads.
Don't get me wrong, I'm happy the gates of hell didn't open up, but it is a little confusing. Is this nature's way of telling me it's better off without me? Were my ferts too low in the normal routine? My test kits are close to worthless, nitrate doesn't work at all, the phosphate kit is possibly OK, but I gave up on it anyway.