Originally Posted by quatermass
Just a thought....
If Excel is suppose to be a kind of 'liquid co2' where does the Carbon come from?
The above image clearly doesn't have any Carbon in it.
And polycycloglutaracetal doesn't seem to have C either.
My guess is, that Excel is so great, because it's mode of action is based on 3 mechanisms:
1. Algicide: the algea are not able to metabolise it and the glutaraldehyde reacts with the cell walls eventually destroying them.
2. it is a C5-Source for the higher plants. they metabolise it. The downside seems to be, that it uses just one CO2 to produce sugar in contrast to anorganic CO2, where 6 CO2 is used. In other words: there is less O2 produced.
3. It is metabolised by bacteria to CO2. The half life of glutaraldehydse in aquatic systems is around 10hrs. That explains why we have to give it every day. So excess will be broken down by bacteria producing additional CO2
I wouldnt overdose it in "usual" circumstances as it can also kill other "useful" bacteria as well as the higher plants. It has been also reported, that Glutaraldehyde is harming the larvea of fish eggs of some more sensitive fish. It is simply a matter of the dosis.