Change in NH4 level or going over some threshold?

[scottward]

The answer to these questions is probably already in a post somewhere, but I haven't come across it (or more likely it just didn't sink in)...

1. With respect to algae spore germination, I understand that the general consesus is that NH4 plays a role here (probably in conjunction with other factors as well, possibly the combination dicating the species of algae that germinates etc etc).........is it simply a change in NH4 level of significant magnitude that triggers the germination, or is it more likely the crossing of some 'threshold' concentration? Put another way, could algae germination be supressed even in the presence of relatively higher levels of NH4 so long as the NH4 level is reasonably stable?

2. It seems pretty much agreed (?) that fluctutation in CO2 concentration will induce algae also, typically BBA. Is this inducement related to NH4 as well? So, CO2 level changes, plants 'freak out' and stop helping manage NH4 (i.e. cease/reduce NH4 uptake), therefore NH4 rises...(and as per question 1 could be either a change or crossing of some threshold that causes the germination)? Or is the germination directly linked to the CO2 drop? Can't be linked to a change in pH attributed to the change in CO2, I can appreciate why that couldn't be the case, but is it possible for a direct algae to CO2 link in some way - or does it boil down to NH4?

Scott.

 

[clonitza]

I don't think the things are really that simple, define CO2 fluctuation: 0-30ppm? 30-60ppm? How's the light, what about plant species, hardscape, soil, water flow? We can barely scratch the surface when speaking of algae 'cause there are too many factors involved and every case must be treated individually not generally. There are tanks without certain algae spores who break all the rules about co2 flow light without having any algae issues. Try put a tank with algae in the same scenario, how is going to look like?

BBA = too much light + unbalanced flow & poor co2 level/distribution.

The general consent of 2011 is to "think about improving plants health and stop thinking about algae".

Mike

 

[dw1305]

Hi all,
I think the argument goes that light (PAR) drives photosynthesis and photosynthesis rates govern nutrient uptake, with nutrients including CO2.

Levels of CO2 in water are always sub-optimal for plant growth and you need to add CO2 to stop the CO2 level being the limiting factor.

If you have high light you also need to provide high levels of nutrients and CO2, so that CO2 and nutrients don't limit plant growth.

If the plants become stressed, because they are unable to access nutrients and CO2 at the rate that the PAR sets, leaf senescence will occur and the plants may leak ammonia back into the water column. Even if the plants are growing at, or near, their optimal rate they are very leaky structures, and over time they will leak metabolites into the water. Higher growth rate means greater leakage and leaf turn-over.

The higher the PAR is the more careful you have to be to ensure that the distribution of CO2 is uniform. This is why the X10 rule, 50% water change, drop checker, removal of any dead leaves and EI were developed.

These high tech "rules" seem to work, but there are definitely exceptions.I think the real answer is that we just don't know, and if you have a method that ensures good plant growth just stick with it.

cheers Darrel

 

[plantbrain]

I think a large issue is the status of the tank also, if the tank is full of fast growing stem plants..........and everything is healthy and in a stable state to begin with, then the tank is FAR FAR more resilient to stresses added.

Much like a Rainforest. There are few weeds and invasive species that do much damage to rainforest. But..if you log and remove the trees, then many things can invade. Restoring the forest back to is original state is near impossible.

Many folks that have algae issues not have a rainforest in that pristine state.........they are less focused on the plants and more worried about algae/nutrients and whatnot.

CO2 is linked to every nutrient, since without the carbon, the plant really can never utilize the other nutrients......or.
.............light for that matter. This causes a lot of stress biochemically.

Once the tank is stable........growing well, then folks can back off many of these things. Most of the lower flow tanks I have seen lack fish or only have VERY few fish. There's the dirty little secret about jamming CO2 into a tank..........then do 2-3 water changes, add even more light, add a few small schooling fish....... then take a picture........

My tanks never fall into this group and none of these idealized slow/no flow systems seem to breed many fish, never once have I ever seen a batch of eggs or fry from such aquariums. EVER.

I find that interesting.