Just one question at this point if i may..
Taking account that the top up on just about any open top tank far exeeds whats exchanged out via water changes over a month/year/years basis....
How does the algae control accumulations of everything thats coming in via your tap water besides N03 and Po4 ?......however hard you try (unless you change out the same as you add in top up on a monthly basis..which is alot)..you are allways 'adding' (via using untreated tap water) pollutants, not taking them away..If your water change water is tap water as well, you effectively cancel out any removal.
Ie what are the algae's utilisation abilities for the various heavy metals, pesticides, and a whole stack of other contaminats that are found to varying degrees in just about every non purified water source..
If your tap water has high Ca,Mg, levels etc which you are then adding to an already balanced salt mix...how are you then balancing (in the aquarium) core element levels such as the natural oceanic balance between Ca/Alk/Mg....?
ok, so thats a few questions....I lied...:tongue1: