[Jamie S]

I have 75gallon acrylic hex tank I started in january. I started to get a diatom bloom (I think) a couple months ago. It started as a light brown covering the rocks and got darker and thicker and moved to the sand and the glass. I hated the look of it and was brushing the rocks trying to remove, stirring the sand lightly etc. It turns the filter sponges brown and nasty! I then stated to get what looks like cyano on the sand and some of the rocks. Then I had an ich breakout so I removed the fish for treatment and left just the 2 nems and cleaner shrimp. While the fish were away i started treatment for the cyano. I pulled some of the rocks and scrubbed them and sprayed peroxide to remove a bit of green algae that was growing, then rinsed and put back. I used chemiclean and and syphoned as much as i could from the sand. It seemed to look better, rocks looked cleaner and cyano gone. I did a big water change and added tims one and only in case the process killed any beneficial bacteria. The fish were then ready to add back to the tank. Its only been maybe a week and looks like the diatoms and cyano are coming back. The water test only showed phospahtes a bit high at .08. Ammonia and nitrates were zero. I added some phosguard to bring phosopahtes a little lower and will test again. The water is clear and I am very particular about cleaning and I want the sand to be white. Should I just let the diatoms do their thing even with how ugly they look? But the cyano can be bad so I don’t know what else to do. I am using RODI water and instant ocean reef crystals. I want to start with some soft corals after I get all this sorted out and thinking of switching to the fritz salt. There was no magnesium detected after water change and not sure how that is possible unless its just bad salt or they don’t have any in it. All of my equipment is HOB, I try to keep things simple. I have a good pump for mechanical filtration and a good protein skimmer. Thoughts???