Soft water high tech planted tank?

Hi everyone! Here's a question...I have noted that there are a number of aquarium plants (Tonina species, for example) that do not do well unless KH is quite low (though most of these are not particularly sensitive to GH). How would one maintain such a hypothetical low KH planted tank? Here's my thoughts on such a tank;
CO2: Yes, constant day and night
FERTS: 1.25 ml NiloCG GH booster per 2 gallons WC water, .075 ml plantex CSM+B per 2 gallons WC water, .0375 ml KH2PO4 per 2 gallons WC water, and .15 ml KNO3 per 2 gallons WC water. Assuming this tank was 5 gallons, this would result in 6.61 ppm nitrate, 1.55 ppm phosphate, 14.93 ppm potassium, and .223 ppm iron being added weekly.
Lighting; Would be shooting for 50-70 PAR at substrate level
WC water: Dechlorinated tap water or rainwater, filtered through activated carbon and DI resin to achieve low TDS. In addition to the above fertilizers, I would add .15-.3 ml baking soda per two gallons of WC water, keeping the KH at about 1-2 degrees. Naturally I would do weekly water changes.

How does this sound? What kind of substrate would I use on this tank? Anything else I should know about keeping such a soft tank? And aside from Tonina itself, what plants would work well in this setup? Thanks

 

This is an awesome project! Few suggestions below:

I'd recommend not keeping the CO2 on 24/7, that's going to be wasting CO2 and possibly gassing your livestock at night.

Is your water already low KH? I don't think the baking soda is necessary for this setup.

You might run into deficiencies with the fert levels you are going at weekly, but it is completely fine to experiment with them. For a lean dosing tank, I like to run at least 10ppm NO3, 15ppm K, and 2.5ppm PO4 weekly at the minimum. If I don't do this, I notice deficiencies, but I also use a lot more light (120-160 PAR at substrate), so if you're using just 50-70, that could definitely work.

I'd recommend using an aquasoil substrate for this type of softwater tank. Some substrates buffer the KH of the water too, so I'd recommend looking into it if you are interested in some sort of buffer. I personally use UNS Controsoil. If you're looking to grow more difficult species like toninas, you're better off using a nutrient rich substrate.

Other species that work well in these conditions include any species from the Lythraceae family. So I'd look into ammania gracilis, ammania pedicellata, rotala macrandras (tons of variants to explore in this species), rotala vietnam, rotala wallichii, etc.

Other species that could work well include the Syngonanthus belem.

 

This is an awesome project! Few suggestions below:

I'd recommend not keeping the CO2 on 24/7, that's going to be wasting CO2 and possibly gassing your livestock at night.

Is your water already low KH? I don't think the baking soda is necessary for this setup.

You might run into deficiencies with the fert levels you are going at weekly, but it is completely fine to experiment with them. For a lean dosing tank, I like to run at least 10ppm NO3, 15ppm K, and 2.5ppm PO4 weekly at the minimum. If I don't do this, I notice deficiencies, but I also use a lot more light (120-160 PAR at substrate), so if you're using just 50-70, that could definitely work.

I'd recommend using an aquasoil substrate for this type of softwater tank. Some substrates buffer the KH of the water too, so I'd recommend looking into it if you are interested in some sort of buffer. I personally use UNS Controsoil. If you're looking to grow more difficult species like toninas, you're better off using a nutrient rich substrate.

Other species that work well in these conditions include any species from the Lythraceae family. So I'd look into ammania gracilis, ammania pedicellata, rotala macrandras (tons of variants to explore in this species), rotala vietnam, rotala wallichii, etc.

Other species that could work well include the Syngonanthus belem.

This is helpful...thanks I am using yeast CO2, so unfortunately turning it off at night would be difficult. Currently working on devising a yeast reactor pressurized enough to create a mist through the diffuser without gassing the tank out...I have a more 'conventional' 5 gallon, with top soil under a sand cap and also around 50-70 PAR at the substrate, that is doing well thus far and keeping the AR 'mini' red and actively growing, but it has a significantly richer dosing regime and the drop checker is consistently between lime green and dark yellow (consistent with my finding that the CO2 causes a PH drop around 1.3 in that tank).

My tap is already low KH and TDS...I just wanted more control over it. This actually originated as a desire for a reef tank...I made a DI filter with some DI resin in a gallon jug, but while it works well I am still apprehensive about starting a reef tank due to the risk of making an expensive salty algae farm like my prior marine tanks. I've fiddled with soft water tanks before with reasonable success (including breeding Parosphromenus 'sentang'), so this is much more comfortable to me.

Two more questions; 1, could I use small amounts of osmocote ferts (1-2 balls per each clump?) to supplement plants that do not benefit from lean nitrate levels? And 2, what fish/inverts would do well in such a tank?

 

A buffered substrate is the easiest and really only way to keep the ph low and stable at the same time. Adding KH will only wear out the buffering capacity faster!

Pretty much any plant and fish from soft water areas will thrive in this sort of setup.

 

A buffered substrate is the easiest and really only way to keep the ph low and stable at the same time. Adding KH will only wear out the buffering capacity faster!

Pretty much any plant and fish from soft water areas will thrive in this sort of setup.

Yeah, I was leaning towards that kind of substrate, though I did not have major PH issues in the past with my low tech soft water tanks. I can skip the baking soda. Thanks

 

This is helpful...thanks I am using yeast CO2, so unfortunately turning it off at night would be difficult. Currently working on devising a yeast reactor pressurized enough to create a mist through the diffuser without gassing the tank out...I have a more 'conventional' 5 gallon, with top soil under a sand cap and also around 50-70 PAR at the substrate, that is doing well thus far and keeping the AR 'mini' red and actively growing, but it has a significantly richer dosing regime and the drop checker is consistently between lime green and dark yellow (consistent with my finding that the CO2 causes a PH drop around 1.3 in that tank).

My tap is already low KH and TDS...I just wanted more control over it. This actually originated as a desire for a reef tank...I made a DI filter with some DI resin in a gallon jug, but while it works well I am still apprehensive about starting a reef tank due to the risk of making an expensive salty algae farm like my prior marine tanks. I've fiddled with soft water tanks before with reasonable success (including breeding Parosphromenus 'sentang'), so this is much more comfortable to me.

Two more questions; 1, could I use small amounts of osmocote ferts (1-2 balls per each clump?) to supplement plants that do not benefit from lean nitrate levels? And 2, what fish/inverts would do well in such a tank?

I'm not sure that you'll be able to grow tonina and other difficult softwater species with DIY CO2. It is too unstable and doesn't provide a high enough concentration of CO2 to really have a thriving system. Unfortunately, it is notorious for causing BBA and staghorn algae because of the inconsistencies in CO2. I've used this method extensively and even when it was optimized, it was very difficult to keep consistent. It is a huge headache at the end of the day.

Yes, osmocote can be used for plants that don't like the lean nitrogen levels. Most fish and inverts will do fine in this system.