You might also call Claus or Troels over at Tropica also since they live right there in Denmark. They can give you some practical advice to aquarist plant growers.

Regards,
Tom Barr

Tom, I see them both every day

Then ask them
I know Troles knows having recently seen the 2 meter behemoth haha.
Tell them "Hi" for me then. And also, when are they planning on coming to the USA or come to the Plant Fest? The Dollar is low right now so this place is pretty cheap.

Regards,
Tom Barr

We've talked about it.. light.. but I still didn't get anything concrete.. mostly it's hearsay, old ideas etc.

Tom, when is the Plantfest? Maybe I'll join in, if Tropica is willing to pay

Oh, and what's the Plantfest about?

Yes, well there's the reference, I cannot find the actual study itself.
I recall looking for it, found it about 2-3 years ago.........read it, then lost the on line paper.

I think there's another similar paper floating around as well.
Main thing is just doing the growth rate studies.

These are easy, Claus and Troels can easily do them also.
Chose 10 plant species and grow them in pots, harvest some for initial weights and growth the rest out. Take their dry weights after and then measure weights.
The tanks should be considered the experimental unit, and you can have say 6-8 tanks with porous light blocking panels and even flow in each section.

This way the tank has similar current, same water, nutrients etc.

Using several species will also help for comparisons.

Dry weights are easy to do and you can measure lots of different plants, combinations this way and the only data is really the weighing on a scale.

Easy.

You need enough replications to make sure your test has enough power.
The same can be done for all sorts of treatments to see what a plant "prefers".

A higher rate of growth is assumed to be "preference" or "the plants prefers the treatment over another".

You can subdivide into root vs shoot growth etc, or even floral parts, turions and other parts like seed production , runner production etc

Generally, if you have 6-8 replications and you cannot tell too much based on Dry weights, chances are that it's not too likely that there's any difference.

If you have significant differences with cool whites vs the plant bulbs and the cool whites are actually higher, then you know something is up

The test you did then is well falsified, thus the plant bulbs are very unlikely to improve plants growth, rather, it's much more likely they just make the tank look better to your eye and all the talk and banter is no more than that.

They put up charts, and other so called data to confuse the customer and market things, not to support their claim.

If they want to support their claim, they would need to show higher plant yields on submersed plants, which of course while rather easy test to do, they will not ever do

Ask yourself why a company might not put up data that disputes their claims from the marketing dept?

hehe

They are not answering the question in any meaningful manner.


Regards,
Tom Barr