Maturing tank help-diatoms and cyano

Jamie S

New member
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???
 
Stop messing with it. You need to let the tank go through the ugly tank stages of diatoms, cyano and hair algae. They will eventually go away on their own...just stay consistent with your regular water changes.

It typically takes an aquarium at least 1 year to fully mature.

p.s. Your ideal of the sand staying white is unrealistic. There are no bright white things in the ocean because everything eventually gets covered in algae.
 
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Lol Thanks for the info. I will see how it goes. What schedule do you recommend for water changes? There is different info out there. Some put on a strict schedule or none at all and some do it based on water testing. And which salt do you recommend for a tank that will eventually have coral?

I just see a lot of pics/videos online with white sand so I thought it was possible in a tank.
 
Diatoms feed on silicates and once consumed, will end.
I change 10% water every week to keep my
Major/Minor elements on point.

It doesn't matter much about salt, many people have great success with RC.

Personally I use RED SEA PRO, mainly because it mixes high in the ranges, is consistent, bucket after bucket and mixes fast and clean.

If your going to get corals upcoming, start getting all 8 parameters stable now.

Stability is everything in this hobby.
 
Lol Thanks for the info. I will see how it goes. What schedule do you recommend for water changes? There is different info out there. Some put on a strict schedule or none at all and some do it based on water testing. And which salt do you recommend for a tank that will eventually have coral?

I just see a lot of pics/videos online with white sand so I thought it was possible in a tank.

I change my water once every 1 1/2 - 2 weeks depending on how busy I am. I usually change 25% of my water while using a gravel vacuum to clean 1/2 of the sand substrate at the same time. Tank stays nice and clear and (after the new tank diatom/cyano bloom) my sand stays fairly white.

Salt - I stick with IO Reef Crystals...been using it for years without issue so I'll keep using it.
 
Most often when you try to maintain "pristine"...Nature will fight back and you will lose.
You have a fish only tank right?
If so turn off the lights and keep them off until the cyano/diatoms are gone..
If its getting a lot of natural light then try to block as much of that as you can.. The fish only need a dim light to navigate/eat..

Keeping the light off removes a major source of energy for both cyano and diatoms.. Give the diatoms time to consume the available silicates and do NOT stir the sand unless you want to prolong that process.
 
Most often when you try to maintain "pristine"...Nature will fight back and you will lose.
You have a fish only tank right?
If so turn off the lights and keep them off until the cyano/diatoms are gone..
If its getting a lot of natural light then try to block as much of that as you can.. The fish only need a dim light to navigate/eat..

Keeping the light off removes a major source of energy for both cyano and diatoms.. Give the diatoms time to consume the available silicates and do NOT stir the sand unless you want to prolong that process.

His original post says he has fish and 2 anemones.
 
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