The point of my initial query had a lot less to do with whether adding phosphates to compensate at the start of cycling aquasoils was a good idea, than wondering how it is that aquasoils cause a scavenging of carbonates and phosphates that are anions given the soil has Cation Exchange Capacity given ait has a net negative charge.
I have been digging into it deeper and am reading up on the internet and still have more questions than answers, but it does seem that while soils have a net negative charge they also have afeas of positive charges at well that do innfact bind anions too, but that the cation binding capacity is greater than the anions binding capacity…
In fact one of thesites I read was specifically saying not to worry about the phosphate issue as the plants could obtain phosphate from the soil as it was still in the tank though not in the water column early on..
Of course that leads me to wonder about rhizhome plants such as Anubias.. i have lost a latge stand of Anubias leaves in a tank once due to an serious outbreak of green spot algae covering leaves of the anubias that then was followed by the leaves melting away. The plant survived, but its beauty was marred and took months to recover. Again I am left with more questions than answers…. Does green spot algae form on anubias leaves because the anubias not have sufficient phosphates, or does green spot algae get triggered from a scarcity of phosphate in the water column? I have heard it claimed and seemed to experience outbreaks of green spot algae in association with very low levels of phosphates in the water column… but again, I have more questions than clarity and answers..
At this point my initial inquiry seems to have been answered that soils have both cation and anion binding ability and the ability to exchange both cations and anions
