Personally I stick to Tom Barr's ratio as best I can. I've been algae free for over 12 months now so something must be right.

Statements that zero PO4 and NO3 are good are plain rubbish. A good idea perhaps for beginners with low plant bio-mass and nutrient uptake but for anyone with more that a little growth then it's asking for trouble. Before I became aware of dosing N, P and K I ran very low NO3 and zero PO4 (using RowaPhos) because I beleived as commonly stated - that zero NO3 and PO4 are good. The end result was a massive infestation of BGA and all sorts of other algae.

Thankfully I have seen the "light" and dose KNO3 and KH2PO4. NO3 - 15ppm and PO4 - 1ppm. I've just looked into dosing K seperately (see my first post).

Just my two pence worth.