[fish_4_all]

Here is the question. Don't read more into it than what is given, please, it will help me get some better answers. The basic answers just don't seem to work here, I need you all to think outside the box!

2 tanks with the same dosing, the same lighting, and basically the same plants have very different growth rates. Both are dosed with Excel at the same rate but one has DIY CO2 injection. The one without the injection is growing plants better than the one with it. All parameters are basically equal and within good growing ranges.

What could be the reason?

 

[tophat665]

Same Substrate? How about fish loads?

 

[fish_4_all]

Same substrate, I would say same bioload. MAybe a slight bit heavier in tank 1 but only because it has 2 BN instead 1 but tank 2 has cories and tank 1 doesn't.