Ivo use to have qa nice run down and I think some other folks spents gobs of time and effort to get at it and use a model.

I spent some $ and can test in real time, in specfic cases, at specific plants, at specific depths etc, with a lot less guess work, time and effort.

That's a trade off.

One I gave some thought too... and also given the lack of light measurement in this hobby, a painfully poor black hole, decided to do something about it.

I see some carry on about testing and measurements of little things such as NO3, Fe etc, but they do not measure light.

Kinda of funny when they bad mouth me suggesting water changes and known volume/weights to target a NO3 levels but they do not even own a light meter

Regards,
Tom Barr