Hi Tom,

I've been reading your posts regarding growing carpet plants like HC using emergent growth. You've mentioned in your posts that once the plants are submerged one has to provide enough CO2 either via CO2 gas or Excel due to the drop in gas exchange rates post submersion. This prevents the emergent leaves from melting and creating a mess in the tank.

I was curious as to whether over time one can lower this CO2 supply gradually and still manage to retain these emergent leaves or whether they would melt away when this happens?

The reason I ask is because otherwise it seems to imply that if you use this technique you seem to be restricted to a more High tech or high excel dosing technique to sustain the initial emergent plant growth.

I would imagine that once a plant is in it's submersed form, then obviously if the CO2 is lowered (within reasonable limits) it will still grow albeit slowly. If it was originally in the emergent form though, you would need to always keep the CO2 levels high enough to prevent melting and the associated ammonia release accompanied by algae?

The one option I can think off that would resolve this dilemma is that if the required CO2 levels to sustain emergent growth is around the same as needed by the same plant with submergent growth to also sustain itself. (The biological reason for this would be beyond my limitted knowledge)

I hope that my questions make sense and that I haven't completely misunderstood the logic behind things. I'm interested in having a medium-low tech tank, ie low light with Excel dosing (but only weekly doses) and I don't want to be committed to having to do higher dosings if I do use this great method for growing in my carpet plants/anubias and crypts.

Regards,

Well, it will be better than not doing it and trying to start with submersed culture.
Plants will already be healthy, well grown in etc.

Either way, you will do well.
HC will do poorly without CO2/Excel.

Regards,
Tom Barr

Thanks Tom. I guess I'm good to go then! Once my Diamond Black comes in I'll order the plants and give it a go. Even if I mess up...atleast I don't have to worry about algae, blackouts and tonnes of water changes .

Btw, if I do use Diamond black along with Flourite Black Sand on top, would I still need to dose a mix of NPK ferts during the emersed growth phase or would the Diamond Black be enough?

Thanks