At some point, when Si is plentiful - it is no longer the Silica that controls the diatom population, but other limiting resources (N,P, Fe etc) Adding more Si beyond that point won't spur any additional growth. I personally saw the same amount of diatoms at 2ppm that I did at 0.2ppm SiO2.
True. I think the bad name that diatoms had previously was almost entirely due to people confusing diatoms and dinoflagellates. Now that we distinguish them with microscopes, we can see that harmful blooms are pretty much never diatoms, but dinos.
filter feeders, copepods, snails etc.
I squirted mine into a powerhead to dissipate the precipitate immediately.
Very interesting. Do you do water changes? I would assume that replacing water will not allow other elements to become undetectable.
My system runs undetectable N unless I dose. Additionally, my system can deplete Fe also - especially if N and Si are being provided. Diatoms can grow quite quickly, so if Si is provided, then something will be depleted and the diatoms will plateau.
Life will explode in numbers until some nutrient/factor is limiting. If phosphate was limiting and everything else is in abundance, algae will explode with the jump to .5ppm. If the amount of algae you have at .1ppm already completely uses up something else like nitrogen (or puts it below some limiting concentration) then raising phosphate won't really increase your algae growth except maybe make something flourish that doesn't mind that low amount of the "something else" (like for example cyano that likes conditions where other things can't grow)
