Alternanthera Reineckii struggling or just settling in?

[_Maq_]

So I don't think mentioning the need for proteins is "off-mark", whatever that means.

Quotation from your quotations: "Their diet consists of both proteins and vegetable matter". THAT is off-mark. Vegetable matter contains proteins just like animal matter.
They do not eat other food than algae and plants because they need proteins, because algae and plants do contain proteins. They are simply omnivores, and mentioning proteins is off-mark.

 

[Hanuman]

• Heavy vacuum of substrate

I suggest you go easy on this. It's best IME to do light vacuums every week on different parts of the tanks unless you are removing all plants and replanting afterwards.

Then I'll leave it a week with the current fertiliser dosing regimen and photoperiod to see what comes of it.

You will need more than a week to properly assess this. You can obviously see new growth in a week time if what you had was an NPK deficiency but it would takes a few more weeks to assess that the growth is healthy and consistent.

I'm tempted by that as well but don't want ot mess with too many variables at once.

I agree. Don't make too many changes at once. This said if you decide to reduce photoperiod, do it progressively.

 

[LightingBamboozled]

I suggest you go easy on this. It's best IME to do light vacuums every week on different parts of the tanks unless you are removing all plants and replanting afterwards.

That's my normal routine but the volume of debris is getting silly and I don't want the population of MTS to explode and then have a die off once the plants stop melting. Needs must this week.

You will need more than a week to properly assess this. You can obviously see new growth in a week time if what you had was an NPK deficiency but it would takes a few more weeks to assess that the growth is healthy and consistent

I'm not changing the NPK this week and only dose micros. So a week will be enough to give me more information on a next diagnostic step. But as far as NPK goes, Nitrates are still rising, Phosphate appears to be high (still slightly doubting the test kit) and none of the symptoms resemble low K as far as I can see.