C02 in river tanks?

[newshound]

don't crypts need less Co2?
isn't Co2 heavier than o2? So it'll "pool" at the top of a tank (above the waters surface).
algae needs longer light times than plants. Algae takes longer to "warm up" when the lights are turned on. If you really want to grow algae leave your lights on 24 hours a day. Note your fish will not like that though.
Doesn't Co2 actually hinder algaes growth?
Is this tank set up yet?
If it is not running I'd turn off the river tank P.H.s and get the plants growing well with Co2 (without fish).

[Rocco]

Tank is still in the building stages, I've put the styro rock background in, now I need to spray paint the back, then I build and test it's manifold, find a nice substrate, clean it, plan the tank layout, build the wooden stand, pre-cycle the filtration in another tank, and so on. I want to do this right and I'm in no rush.

I'm also setting up an attempt to breed corydoras sterbai.

[crazy loaches]

don't crypts need less Co2?
isn't Co2 heavier than o2? So it'll "pool" at the top of a tank (above the waters surface).
algae needs longer light times than plants. Algae takes longer to "warm up" when the lights are turned on. If you really want to grow algae leave your lights on 24 hours a day. Note your fish will not like that though.
Doesn't Co2 actually hinder algaes growth?
Is this tank set up yet?
If it is not running I'd turn off the river tank P.H.s and get the plants growing well with Co2 (without fish).

"less" is a relative term. Crypts are often slower growing so they would be more apt to do well in a lower tech low co2 type tank. So compared to a higher light high growth tank, yes, they would require less co2. However they will grow faster with higher light, ferts, and as such demand more co2.

There is a lot of debate about algae and light. I do not believe algae require a longer photoperiod than plants. If anything algae is more opportunistic than plants. I think this belief stems from the fact that it is much more common to have algae issues with longer light cycles. This has nothing to do with algae liking the longer light cycles, more likely it is about the light being out of balance with the plants, nutrients, and co2. Plants typically only need about 8-12hrs of light. Many folks do the 'noon burst' were only high light is used for a few hours in the middle of the photperiod, to simulate noon sun.

I dont believe co2 hinders algal growth per se. Algae is like an opportunistic predator that looks for scraps. Whenever there is too much light, it uses it. Plants arent utilizing ferts? Algae will. The CO2 helps the plants to grow and use light and ferts. If the plants are growing well and uptaking nutrients and co2 and everything is in balance algae is typically kept at bay. Dont have enough ferts and the plants stop growing, then algae can utilize the remainder of the ferts. Remember that if one nutrient is in excess, that doesnt mean its the cause of algae - first look for another nutrient that may be too low and cause the plants to stunt and not be able to use the others (so the others appear in excess).

Another way to look at it is algae and plants are very similar and uptake nutrients and utilize light. But we have some control over what we want to grow. If you have lots of plants and provide them with appropriate conditions the youll be growing plants. But if something is out of balance then algae will grow. Algae most often comes from insufficient co2, insufficient nutrients (NPK+traces), or excess light. Many think its from too much nutrients but in a heavily planted tank this is rarely the case. Here are a few examples: black brush algae (bba) is associated with too low co2 levels. Green spot algae (gsa) is from insufficient phosphates, and cyanobacteria (bga - blue green algae) is often triggered by nitrates bottoming out. These have been studied and results can be reproduced, and assumes most all other variables are held constant. And I dont remember exactly, but I believe Tom Barr (a plant guru) has done some testing by increasing nutrients to really high levels. He could not get an algal outbreak by increasing any single nutrient to very high concentrations (I dont know the specifics off hand though).