Few water supplies do NOT have silicates.
Unless you plan on removal, most folks would have to do a fair amount of extra work to deal with this.
Check around at the levels in taps waters.
The research I've seen concerning PO4 and algae over looks the plant's PO4 bound up except in a few cases in some research here in FL.
When they added the PO4 that is in the plant biomass and compared it with an algae dominated lake, suddenly there was no correlation with lake algae/plant domiance and tropic PO4 gradients.
They had been including the phytoplankton PO4 components in their algae dominated systems but not the plant's PO4. Doh!
There is a good deal of research done out at the Water conservation area 2, west of Miami, south of Okeechobee. Regarding plants, periphyton and tropic gradinets also.
Adding PO4 changes the plant communities as well, not just the algae in natural systems.
Plants need a higher amount of PO4 than algae also with the same biomasses.
Myths.............well there are many. I've pissed off everybody at one point or another over many of them. Neil Frank and I went around and around. Algae and PO4 still bother him and likely Art as well.
It's somewhat relgious in nature in a joking manner, the gospel. Blasphemers are not taken lightly.
But sometimes you get lucky and don't get burnt at the stake or nailed ot cross.
I never "dioscovered" that high PO4 does NOT cause algae, it was Steve Dixon. I had the tank, he did the test, scratched his head quite a bit after testing my tap and tank water which was about 1.2ppm PO4, and then added PO4 to his limited tank and it was his questioning about how this could be the case that led to me bothering people over it.
I was more concerned about the substrate back then.
Other myths generally:
RFUG's are bad
Cables are needed
Substrate fertilization is needed,
high light is needed
CO2 enrichment is needed for many plants
RO water is needed
Plants prefer soft water
Pennywort drinks taste good.
Discus or picky fish are not compatible with plants.
CO2 will not help a lower light tank
Antibiotics are needed for BGA
I think the independent variables are often not considered(The CO2, light, NO3 and so on and the PO4 is manipulated), causes many to think one causes another in their tank and then they believe it and assume it to be true. Later it becomes repeated and multiplied.
Regards,
Tom Barr