Me and my husband have different thoughts through reading and general research from these threads. Our tank is cycling, we had nothing in it except for live rock and sand for 2 months, then added some coral…..now have fish for about 1 month. We were having little to none diatoms/cyano but when we did, we would do a water change, less light etc. it’s been a couple weeks and everything has been great, water parameters, coral happy, fish happy. My husband decided he wanted to do a water change anyways. I said to let it lie while things are good, we have a Red Sea reef mat, skimmer doing a lot of the heavy lifting. As soon as he did the water change, we now have a massive bloom of diatoms. So we will do a water change again. My question, when things look good, do we need to do a water change? Or why mess with a good thing? Thanks for your help!