Should I be starting over after 5 years?

[TheMacInnis]

Hey, everyone-

I've kept a beautiful 50g tank for over five years, and it feels like the tank has run its course. While the fish are healthy, the plants have become something of a monoculture of broad-leafed crypts (C. pontederiifolia or similar), and the introduction of additional species marks a slow march back to near-monoculture as they don't flourish.

Some basics on the setup, followed by some questions:

- I keep the pH at 7.5, a moderate GH (60-120ppm) and a moderate KH (80-100ppm)
- Zero nitrate/nitrite
- I dose pretty generously with Flourish Potassium each day, and Flourish Trace every other day
- Every few months I add iron (etc.) soil spikes (ADA)
- Plenty of light for 8 hours a day (ADA metal halide 150W); no algal problems
- CO2 injection between 3-5 bubbles/second
- Substrate is ADA Amazonia, and it's 5+ years old
- 20-30% water changes every week, like clockwork
- And, yes, I'm one of the suckers who bought the Fluval G3, which is fine; the mechanical filter needs weekly cleaning (but really begs for, like, 2-3 times weekly cleaning, because the flow chokes off! annoying.. but I digress)

Over the course of the last few years, I've had blooms of snails... now I have no snails. At one point, the tank was utterly packed with competing plants I had to trim every week, including gorgeous dwarf baby tears.. now I couldn't grow dwarf baby tears to save my life (I tried). I have had the fish (Emperor Tetras) breeding almost every month.. now they don't. Shrimp used to have a great life... now they don't last.

The aquarium seems to have been through a weird cycle of life over the last few years, despite my meticulous care.

Smaller questions:
- Why the heck is only the crypt flourishing? What characteristic of the chemistry am I overlooking?
- Is it possible that this is really about the substrate? Is it completely depleted?

My big question:
How often do you decide to "start over" with your tank? Same equipment, etc., since it's all perfectly fine, but clean it out, replant, new substrate, new layout, etc.? Am I an odd person for nursing the same tank along for 5 years?



Thanks!
-tm

 

[PerfectDepth]

- Why the heck is only the crypt flourishing? What characteristic of the chemistry am I overlooking?
- Is it possible that this is really about the substrate? Is it completely depleted?

If the crypts (heavy root feeders) are flourishing, then I'd say the spikes you're using are supplying plenty of nutrients.

Here's a likely answer to your first question

- Zero nitrate

Shoot for at least 10-20 ppm, you will likely need to start dosing phosphorus as well. The reason crypts are not affected is because they do not feed from the water column much at all. Other plants such as stem plants need nutrients in the water to thrive. Also, if pH is 7.5 when the co2 is running, I'd say the co2 is probably not being sufficiently dissolved for some reason. Do you know how far your pH drops during lights on?

As for when to reset.. it really depends. The ADA substrate might be really muddy after 5 years, making planting and uprooting very messy. I'm not sure how long it generally lasts before turning to mush.

 

[Mebbid]

The big thing im seeing is a lack of fertilizers. The floruish line of ferts are basically crap for anything but a low light tank.

I would recommend getting into pps pro or ei dosing of dry ferts. I would bet switching to that would help other plants flourish.

 

[TheMacInnis]

Thanks, guys.

Also, if pH is 7.5 when the co2 is running, I'd say the co2 is probably not being sufficiently dissolved for some reason. Do you know how far your pH drops during lights on?

Based on some other threads, I upped my CO2 dose to 4 bubbles per second. After a day at this setting, the pH now drops to about 6.8 toward the end of the day. That seems like a stronger reaction to the CO2. Is this about what should be expected?

I would recommend getting into pps pro or ei dosing of dry ferts.

Google is my friend! I chased a bit more info on EI dosing, and it became immediately apparent that the advice I was given to focus on Potassium seems bogus: I need to dose the other macronutrients. I'm worried about algae, but I'll keep an eye on it.

Thanks!