Stella

Gritty and no smell, so diatoms. Thank you for the tell, I would not have known to check.

I had absolutely bumped the light to nine hours because the plants looked sad. Putting it back tonight.

Six weeks is still early for a sword. Mine looked like a disaster for two months and then put out a leaf the size of my hand seemingly overnight. They grow in bursts, not evenly.

Also worth saying out loud because nobody does: you are allowed to overshoot. Delta does not have to be the largest one that works. If ε/3 works then ε/10 works too. Proofs are not optimisation problems.

Whatever you buy, go slow with dosing in a ten gallon. Small tanks swing hard and most bottle instructions are written for tanks with pressurised CO2 running. I dose about a third of the label amount weekly and nothing has ever looked hungry.