Hello, all. I just set up a new aquarium, so far, so good. here's the details: 10 gal halfmoon, natural gravel & rocks with live plants, setup with laterite in the gravel, RO h2o, bacteria culture, stresscoat,and added 2 red tux guppies (m) to start. I keep a lab notebook, and am using API test kit to monitor. the tank came bundled with a crappy heater, so I immediately replaced it with an adjustable one. The filter will also probably need to be replaced soon. 2-3 days after addition of fish, the ph dropped to 6.0 or below, so last night I added a few sea shells to the tank, plus </= 1/16 teaspoon baking soda. this am, ph is at 6.4. I will be vacuuming the gravel this weekend and changing 10-20% of the h2o, re-checking ph, & making another slight adjustment if needed. Any other advice? Setup was last sunday, with plants, the fish were added tues night. I'm planning to add more fish gradually.