1) Macro Algae. You can PM Blueheaven, he is the Chaetomorpha farmer, he should be able to sell you some from the recent harvest.
2) Lime water = Kalkwasser. Kalkwasser cannot be pour into the tank. You need to drip it slowly into your tank at lights off. First mix Kalkwasser with dechorinated tap water and let it settle, drip only the clear top solution into your tank.
Kalk dripper can be DIYed by insering a Plastic Air Valve 1 inch from the bottom into a Plastic Container (Soft Drink Bottle).
3) Phosphate Medias = Rowaphos, Purephos, Elimphos, BioPhosII etc. They work best in a Fluidised Reactor. If you dun have a FR, can try Poly Filter Wool.
HTH