For low tech tanks, you just have to allow more time for the plants to develop new healthy growth (it'll be alot slower than compared to high-tech tanks)... in the meantime, they need sufficient nutrients to avoid deficiencies (but not too much, due to lack of Co2 and low light) and consistent parameters to avoid algae issues which interfere with their growth.
If you have livestock in the tank and feed them regularly, the food and waste will usually generate sufficient nitrogen and phosphates for the plants (especially if the plant density is still relatively low in the beginning). Just dose trace/micro and potassium fertilizers to make sure the plants get a sufficient range of nutrients.
Only if you start spotting macro nutrient deficiencies in the plants, then dose those specific nutrients in controlled amounts and observe the effects, while adjusting the dosages accordingly.
Other than that, just have to wait for the plants to grow out...
alot more patience is needed for low-tech tanks.
In the case of your tanks, the carbon supply needs to be increased first (ie. Co2 injection), then the lights and nutrients can be increased accordingly to match it and achieve a balance for enhanced plant growth... otherwise if you only increase the lights, the plants may not be able to utilize it effectively due to carbon limitation and all the excess light and nutrients will just feed algae instead.
Bookmarks