I will open up this post with my official Goal which i believe to be a common goal among fish keepers. I began this in hopes of setting up a low maintenance tank for my parents, but i think it has changed a bit in my own mind and perhaps the fish keeping community could benefit from the discussion. I will appreciate anybody's input should they have any!
: to set up a freshwater
aquarium with absolutely minimum maintenance (how much and what kind of maintenance would qualify as minimum?) besides feeding fish while also maintaining high quality living conditions for aquatic inhabitants (20 or less nitrates possible goal? Additional measurable goals?)
40 breeder + 20 gallon sump (around 55 gallon system when full)
Bare bottom display with a few large pieces of lace rock as decoration.
2 brs reactors from the saltwater phase of the tank. One is filled with marine pure chunks (MP2C-C) while the other will be filled with 1/4 cup of carbon replaced monthly.
Use brs rox 2.0 carbon to help remove nasties from tap water top off and fish growth hormone (if it can do that last part… I couldn't find any for sure info on that. Any other recommendations of better media to use for that purpose?)
No heater (they are koi after all…). May affect tropical plant growth.
Installed proper grow light (https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
) 9.5 inches over the water level in the sump which has 1 square foot of surface area to grow my plant of choice water lettuce. (Any evidence of better plant to use? I wanted to have a plant that can put on loads of biomass and use atmospheric co2 (no dosing co2!!) to help speed up growth to absorb all ammonia before it converts into nitrite or nitrate by the bacteria in the marine pure.)
Using seachem safe as dechlorinator for initial setup and top off water.
Tap water very hard and high ph.
Progress and updates thus far
During fishless cycle, nitrates rose out of readable levels (over 400) over a period of 3 weeks.
Added 3 water lettuce plants. They pulled out all remaining ammonia and dropped nitrates to around 80 in a couple of weeks. The plants quickly covered the majority of the area available. Currently on for 8 hours a day. However, they are getting slightly burnt leaves. They may benefit from being farther from the light source.
3 koi that were 2.5 inches long added. Should be tolerant of variable water quality and produce lots of waste to properly test the system. Plan to remove once they reach around 8 inches or once next spring rolls around (get them into a proper pond once i’m done with them!)
Feeding four times a day 1 heaping spoon full of discus
bio-gold (I had the small sinking pellet on hand, so I may as well use it!). Adds up to ½ teaspoon a day. I can try and get the weight later if anybody is interested.
Add capful of flourish every week to help maintain strong growth to maximize ammonia consumption. (this may be eliminated. especially if i would be attempting something like an algae scrubber, however i believe those would be higher maintenance than the setup i am attempting due to algae needing cleaned out more often than a larger plant like water lettuce.)
Nitrates do not raise over 80, but don't drop below 80 either.
In the first 4 weeks of having fish in the tank, i did a single one gallon water change to siphon out detritus in the plant growth tank/settling tank. I found out that there is also a lot of daphnia and an unidentified worm that seems to build tubes out of detritus that they live in. I doubt either can/will harm the koi.(but help on identifying the worms would be helpful!)
I intend to run the system until the plants can't keep up with the waste production. then i will know how much food a square foot of grow area can process. from there, it should be easily scaled up for bigger systems if the food input can be guessed.
new questions raised thus far in my experiment (i have no answers but may appreciate input on them)
If the nitrates were removed with a water change, would they raise again? Or would all ammonia be absorbed directly by the plants? infinite zero nitrate through direct ammonia absorption?
With this method, if the ammonia can be handled by the plants, should the biomedia be removed entirely to reduce the amount of ammonia turning into nitrates since plants prefer using ammonia and may not use it as readily once it is converted to nitrate?
How much surface area for growing will be required to keep the nutrients in check? When the system fails, what will be the main cause?
If set up correctly, could the tanks used for holding the plants be set up to function as settling tanks and produce as good water clarity as filter floss?
Would it be beneficial to set up three separate plant holding containers and have lights on each run 8 hours. When one turns off the next turns on to have plants at all phases of growth all day? Or do plants absorb ammonia all through the day and having the cycle set up like that be unnecessary?
In summary, my direct questions to you all are as follows.
How much and what kind of maintenance would qualify as minimum maintenance?
What would be realistic goals for water quality to try and aim for in a system like this?
Can carbon remove fish growth hormones from the water to prevent stunting?
Can anything remove fish growth hormones from the water to prevent stunting?
Any better plants to use to absorb nutrients?
Can anybody identify the worms on that terrible description?
I want to try and gain as much info during this process so that both I and the fish keeping community can learn. A fish keeping method like this could also help dramatically reduce water usage while maintaining water quality for the animals which would be especially useful for systems 180 gallons or larger (which is the direction I would like to take the experiment in the future if it passes the preliminary test now). Thanks in advance for the advice, criticisms and questions!