Tropica Nutrition Capsules - 50 pcs Slow Release Plant Fertilizer for Indoor & Outdoor Plants | Perfect for Houseplants, Gardens & Hydroponics

Put three of these into deep gravel in a 20ltr shrimp tank late one evening for some corkscrew vallis, next morning the top of the water surface was coated in thick soapy bubbles, then noticed dead shrimp. Water test showed ammonia 1.5, nitrite 2.0 and nitrate 40. This tank has been stable for 9 months and since the filter matured (fluval edge hob) the only reading came from a trace of nitrate. It took four days of twice daily 50% water changes and overdosing with Prime to start to get things under control, still having to do one 50% water change 6 days after putting the capsules in as nitrite still showing, the sudsy bubbles went after 3 days. Nearly all the shrimplets have died and at least 15 shrimps. Not a nice experience.