That all looks normal to me on a tank with no CO2
Running that much light, and giving plants that much access to nutrients, you'll be bottoming out on CO2
for sure stalling growth, and allowing algae to creep in.
You plants aren't deficient in one nutrient, it's a combination of higher lighting, no CO2
, and a non-refined fertilizer regime.
I would start by dosing Flourish excel at the after water change rate once per day (You've got vals, so start low and slowly work up to these levels over a few weeks). I would also stop doing the extra Flourish potassium, no need for it if you're dosing Thrive.
I would also strongly consider all these steps:
Reduce light intensity if possible.
Reduce photoperiod to 5 hours per day max (until algae has subsided, then slowly increase back up to 8 hours per day over a few weeks).
Ensure you are providing adequate nutrients for the plants (unhealthy plants promote algae).
Dose Flourish Excel or equivalent Met14 at the “after water change” rate on the Excel bottle once per day.
Manually remove all algae you can.
Manually remove excess organics in the tank by gravel vacuuming and cleaning filter media in old tank water every water change.
Manually remove any decaying or dead plant matter.
Increase water change frequency, and the amount of water changed.
Consider spot treating badly affected areas or dipping plants / hardscape in a Flourish Excel, Met14 or H2O2 + water solution. Google search which method you think would work well, and for general ratios to mix a safe solution. Certain plants can’t tolerate these chemicals, so ensure you do a little research prior to dipping / spot treating plants.
Seachem Excel is not a carbon source, it is not CO2
and it is not a CO2
replacement. Aquarium product manufactures are masters at marketing, and mislead the buyer with many products.
Excel is a mild algaecide that allows users to run slightly higher light with a reduced risk of an algae outbreak. It may or may not help break down protein films growing on plant tissue, allowing plants better access to atmospheric CO2
naturally occurring in the water.
Excel can be used to spot treat, and create plant dips to help control algae.
Excel should be used as an algaecide, not a carbon or CO2
source / supplement.