What 2 Do Next?

Well, Richer would suggest covering your tank with a blanket or a black garbage bag making sure no light can get it and leave it for a few days. That should get rid of the algae.(turn off CO2)


If you put crushed coral in and the CO2, they would offset each other with the p.h. because the coral raises the p.h.

My suggestion would be to add as many plants as possible that are good nutrient users. Crypts are great plants for a low light tank, but don't use nutrients very quickly and swords are only somewhat better. Wisteria would be a good choice. I understand that anachris is another. Floating plants such as water lettuce and salvinia and frogbit use a lot of nutrients.
Now would also be a good time to start a DIY CO2 bottle as well.
I wouldn't worry about your pH dropping to a dangerous level with the numbers you give for kH with only one bottle.
You are,IMO, experiencing a normal newly set up tank problem, with algae. The more fast growing plants you can get in there the better. And they are fairly cheap. Let them take over the tank and the algae will probably decrease.
If you are not doing it, a weekly 30-50% water change will work wonders in keeping your water clean and supplying many elements needed by your plants.
Lastly, read everything you can in our archives regarding fertilization and THEN decide what you need to start with. Go to the search button(upper right of page), type in either fertilization, nutrients or Plantbrain. Dosing without knowledge, sometimes is worse than not dosing at all.
Len