My planted nano-aquarium Saga
Hello everyone, new member here :-)
A brief intro: this is my first ever aquarium, but I've had some experience with a somewhat similar hobby in the past.
I was given as a gift a Fluval Chi tank (19 Liters/5 US Gallons) and then I started adding all sorts of things. The external pump is rated at 200 Liters / hour with a capacity of 3 Liters, whilst the light is a Toshiba E-Core LED, rated at 19.8 Watts but equivalent to 30 Watt fluorescent. This gives me around 4 Watt/Gallon and up to 6 Watt / Gallon depending on the LED marketing hype. The LED is rated at 6500K and due to the small fish tank, it really penetrates down to the bottom.
I have planted dwarf baby tears at the foreground, and dwarf haigrass at the background. I used as first layer a type of fertilised soil I bought from my LFS (sorry don't remember the brand) over which I've added roughly two inches of gravel (I know, I should had bought ADA soil).
My experience so far has been very mixed. The tank has 3 neocardina shrimps, 3 cardinas shrimps, 2 nerite snails and 8 cardinal tetras. I know what you'll say, that it is overcrowded, but I assure you the heavy filtration and frequent water changes, keep ammonia and nitrite to zero most of the days (more on that later).
My problems started with algae: I've had almost all types of algae so far: brown algae, fuzzy algae, hair algae, blue-green algae (cyanobacteria) and lately I'm back to brown hair algae.
Last week, my Co2 bottle was depleted, because I was under the stupid impression that tightening it by hand was enough. During that week, there was no Co2, and I got a bad cyanobacteria infestation, which was spreading over the dwarf baby tears. I would remove all signs of it using a toothbrush, and two days later it would come back even stronger. This started before my Co2 bottle leaked, but got much worse during the leak. At which point, I decided to take drastic measures.
I used pharmaceutical grade hydrogen peroxide at 3% concentration, by stopping the filter and dosing using a syringe, 1ml or less on the infected areas. I did the treatment for 3 days, and indeed after that, I stopped having signs of cyanobacteria (or other algae). After the treatment, I upped the co2 to 30ppm.
However, due to the hydrogen peroxide, I ended up with a lot of dead plants, and decaying organic matter. I could (and still can) see white earthworms feeding on the decaying matter, my ammonia spiked to 0.25 ppm and my Nitrite spiked to 1ppm, whilst Nitrates where at around 5 ppm.
I did a 50% water change using RO/DI water only, and kept of feeding every other day, and now ammonia is down, whilst Nitrites are at 0.25ppm. I also dosed live bacteria boosters.
One week later, no signs of cyanobacteria, and the fish appear to be healthy. However, I am still having issues with plant health. I used a wrong (very wrong) EI dosing regime, which I have since corrected (bough a digital scale and fertiliser salts, and I'm not making my own solutions).
My issues are with TDS/PPM and water parameters:
My tap water has a hardness of 7 degrees or 185ppm using a TDS meter.
The Carbon hardness is around 100 ~ 120 ppm.
By using RO/DI water, I can bring the GH and KH down, but due to the Co2, my PH also comes down. PH from the tap when Co2 injected stabilises at around 6.8m but when using RO/DI it goes down to 6.2. Cardinal Tetra seem to be OK with that range, and so do my shrimps.
However, most sites recommend a GH of 6 degrees (100ppm) for cardinals. Currently, after dosing with my EI ferts (3 times a week, one 50% water change) my TDS stands at 320 ppm, however I have now added Magnesium (MgSO4). My Trace is already mixed, and I intend to also dose some Chelated Iron. The reason for all that analysis, is because the dwarf baby tears appear to be deficient (of either NPK or Iron) as they have a lime green almost yellow colour. Also, I've noticed that since I nuked the tank with hydrogen peroxide, and upped the Co2 and nutrients, I am getting significantly less algae.
So, what is a good limit of TDS/PPM? Considering that my tap comes at 180ppm, and I'm now at 330ppm, there is probably a small excess of nutrients (also, the organic decomposing hasn't finished, there's still a lot of decaying plants).
What is a good balancing point, between the Tetra's 100ppm/6 GH preferred hardness, and the overall TDS needed for me to fertilise the plants?
If I add a lot of RO/DI water, I bring overall GH and KH down, but my PH also drops due to fertiliser salts and Co2 injection. The dwarf hair grass seems very healthy, whilst the dwarf baby tears could use the increased nutrient levels (or so I think). The indication that I get less algae seems to suggest I am on the right track, but I'm still worried about the health of the fish.
The tank is now 4 months old, and whilst I ruined the biological balance with the hydrogen peroxide, my ammonia-nitrite-nitrate params are almost zero, and I'm hoping once the entire plant matter has been composted, they will be back to normal. In the meantime I intend to keep doing water changes every 3 days, and feeding the fish every 2 days, so If I am to stabilise the nutrients, PH and hardness, I guess this is the best time to do it.
Many thanks in advance to anyone who can help.