fragile pogostemon

[heindrich]

hi,
my first post here.

I'm not so new newbie any more, have had aquariums some years now.
Custom 90 gallons aquarium currently.

I have problem with plant growth I cannot find answer to. Namely, almost everything is growing quite well, some plants (tenellus, acicularis, verticillata) are reaching in height more than 3 times of sizes like Tropica lists them.
But I can't grow any pogostemon species. Helferi and stellata are growing very small and fragile. Why is that?
Dosing is more or less EI, currently trying high phosphate, no diff.

little background info - KH-4, pH-6.8, light 240W at midday for 5 hours, 80W rest of the time.

 

[Tom Barr]

CO2 is tad low.

I aim for a pH(assuming the KH is accurate) of about 6.5.
Try aiming CO2 mist or the output directly into the plants.
That and good stable NO3 dosing ought to resolve things for you.

Regards,
Tom Barr

 

[heindrich]

Yes, indeed.
Cutting down on PO4 and adding more NO3 seems to help.
Filter output with CO2 reactor on it was already aimed at it.

Thank you.

 

[Tom Barr]

Also lower light helps this plant which is fairly easy to grow under slower conditions(less light)

Regards,
Tom Barr