Hi everyone, new to this please bear with me. Added plants 4 weeks ago and fish just last week, I have a 300 gal fish tank with a 110 gal reservoir 3 grow beds @12" deep, 2 - 3' x 6' and 1 - 3' x 5', also 2 - 4" x 10' lettuce beds (continuous flow). I have issues with PH too high running at 7.8 +, and alkalinity running at 40 ppm. tried a few different types of pH down without success and tried raising alkalinity using baking soda, no luck. Now I have oyster shells in the reservoir trying to raise my alkalinity, this is my second day with the oyster shells and it dropped to 20 last night and this morning it was back up to 40, pH the same at 7.8. Using a 14" x 14" bio filter pumping 600 gph through it changed that yesterday to the new setup. going out to check my levels again this evening. How long will it take to change my levels from where they are to a workable level? I lost 5 Commit Goldfish, not sure why, they just started swimming slower and slower then stopped. My DO is.....well it is the right color on the chart, not sure how to read the graph, but I added 8 drops of the third reagent D, so I'm guessing my DO is ok. HELP! Please.