Warning: long post ahead! But bear with me and ye shall be rewarded with future trimmings.
Before leaving for college this summer, I thought I had all my bases for my 120 covered: lights on timers, auto-dosing with peristalsic pumps, CO2 level as high as the fish could take it. I returned last weekend after two months, and the tank was literally a box of BGA. Turns out the CO2 solenoid, which I had used for over a year, stopped working, meaning no CO2 got into the tank. My crypts and buces were still alive somehow (albeit less numerous and healthy), but almost all stems were dead. The long weekend became a rescue operation, cleaning out as much BGA as physically possible, and then buying as many cheap weedy stems as possible to get sufficient plant mass back. I also received a new adapter for the solenoid, so CO2 is flowing once again.
This is the tank as of now. It's not much, but considering its state only six days ago I'll take it. The hardscape needs a bit of work, but I'll get to that next time I'm home. Beyond that I plan on eventually replacing the stems on the right with Rotala rotundifolia, R. nanjenshan, etc.
The crash made me reflect on the tank's past, which to be honest wasn't too rosy. Certain plants grew quite well (Rotala singapore, R. macrandra 'green', Crypt affinis ''metallic red'), but there were a lot of issues, even with high light (two Marineland Aquatic Plant LEDs and a Monster Ray, though the latter is switched off for now), pressurized CO2, high flow (Eheim 2217 and a cumulative 3000 GPH in powerheads), and soft water.
1. I had to keep the CO2 levels so high that it severely affected livestock. I couldn't keep any fish besides otos long-term, and any inverts didn't make it for more than a few days.
2. Even then, many plants had difficulty growing, looking to be of mediocre health with weak lower portions - only the very tops looked good (if even that). Even the ones that grew well did not grow as fast as they seem to for other folks and had mediocre-looking middle and bottom portions, not quite like the perfect specimens other people seem to grow. The only plants that were in superb shape were the crypts - I actually had a really nice carpet of C. parva before the BGA devastation!
3. Filamentous algae was always quick to take hold, despite regular manual removal and seemingly high CO2 (different iron levels had no impact)
4. Organics buildup was very quick - mulm would already accumulate just days after each water change. Ever-present surface scum required a separate skimmer to deal with. And all this with at most a dozen otos!
Looking back, some possible causes were:
1. Lack of regular filter maintenance (now remedied; it will be getting cleaned once a month - I hope this is enough?) probably contributed to rapid organics accumulation and thus algae
2. A very large piece of driftwood with moss on the right side of the tank (around where the wisteria is now), now gone (moss was dead and it didn't fit my scape anyways). This provided a harboring site for algae and a source of organics (trapped particles, dying moss, etc.). It also probably impeded flow and CO2/nutrient distribution, which could also explain poor growth despite seemingly high CO2.
3. Inadequate CO2 - even though I was pumping so much gas I couldn't keep much livestock and was going through a 20 lb tank every two months, the mediocre or poor plant growth (depending on species) combined with lack of signs of light or nutrient deficiency and algae issues suggests that my CO2 usage wasn't quite optimized. Poor plant health probably also contributed to organics.
4. Insufficient algae eaters - seeing that shrimp never made it more than a few days, there was nothing to eat hair algae (it was the soft type, not the hard wiry stuff that nothing touches). With a dozen otos, my glass was very clean of GDA. Maybe lack of scavenger fauna to eat dead plant matter also contributed to the rapid organics accumulation.
The first two causes are now resolved, but the last two still need resolution. Currently I can just crank CO2 really high as I only have an oto as the lone survivor of this whole fiasco, but I would like to keep more fish in the future so need to brainstorm some solutions.
Here are my goals:
1. Optimize CO2 usage
to a) have lush healthy, and fast-growing plants (even more difficult ones) while b) being able to keep shrimp as algae eaters and fish as livestock, as so many people on the forum do. Admittedly I had terrible collectoritis, and will grow many less species than I once attempted (9 types of stems alone!), but even then I would like to grow a nice healthy red Rotala variety like macrandra or butterfly as a focal point.
2. Minimize organics buildup
to prevent algae issues and make maintenance a bit easier.
To achieve these I figure there are two issues I need to address
Given the past of mediocre growth despite an extremely high rate of CO2 usage and adequate light and nutrients, I suspect inefficient CO2 supplementation to be the issue I need to address if I want to keep both thriving fish and plants. Currently my method of diffusion is an Ista Max Mix reactor (large model). However, once the gas starts flowing, the reactor becomes anywhere from half to almost completely full of air! This was actually how I confirmed that CO2 had stopped flowing and the solenoid had stopped working.
But after some research, this does not seem to be normal and may be suggestive of inefficiency.
What diffusion method should I use to most efficiently utilize all the gas and ensure full distribution?
Would another reactor be better? What about a mazzei system? Anything but a standard diffuser would be fine; I hate the bubble soda look and I feel they can become irreversibly dirty & lose effectiveness.
Hopefully with the intrusive piece of driftwood originally placed by the spraybar and powerheads now gone, the tank will experience improved flow. However I am really hoping to optimize flow for both nutrient distribution and minimizing organics buildup. The frontmost powerhead was originally in the lower back right corner; I raised it to avoid uprooting the new stems. It's now angled slightly towards the front glass, while the big powerhead behind it is angled parallel to the front glass.
Is this a good configuration or should I further adjust it?
How much surface ripple should I have?
Since my family are the ones who view the tank on a regular basis and help me maintain it, I would like to reward their efforts with a nice tank with healthy, vigorous plants and livestock beyond a few otos. Imagine a school of dozens of Boraras brigittae and some chocolate gouramis in there! I would like to make it so that the maintenance needed is pleasurable, such as trimming plants, rather than removing cups of hair algae every few days. Any input and ideas are appreciated; thank you for making it this far!