Good morning. I should have done an intro before my first post but a little late than never! My name is Molly. My husband and I put in a 20,000 gallon koi pond this past summer. We welcomed 20 koi to our pond. Our koi decided to spawn in late August thru September! We had no idea till we started seeing little colors all around the rocks!! We are so excited to be newbies and have the opportunity to try to raise a few ignore own. So along with some advice from a pond enthusiast and our desire to see them (and give us something to do) we put a 300 gallon tank in the basement. We have an external filter system, two air bubble pads, and I am trying to see if I can winter a few hyacinths. Which right now is working out because I have to soak the food and the smash it for many of the babies to eat and I smash it along the plants and they love to nibble it along the plant. I have about 200 babies in there for about 3 weeks now. I had original just pumped the pond water into the tank so I could hopefully save some stress on them. I am still having trouble with getting the water balanced. I took a sample to our pond store and he was only concerned about the PH behind was 9. So he advised vinegar. Which I am not sure it helps. Maybe short term. But I have a sweeper and have been sweeping every other day to remove waste. I have to bags of carbon ammonia remover hanging in there. I have been adding beneficial bacteria 2 times a week. I am not sure I should but the filter flow seems to be slowing and so I have washed the filter pads but been careful not to touch the bio balls. The filter has an inbuilt UV light. Should I just relax and give it more time to cycle? And also, I will attach a picture. I was cleaning the roots of the hyacinth off yesterday thinking that may help and this was in the roots. Does anyone know what it is?? Thanks for all your help so far, and so excited to have this place to find information!!!