Algae popped up seemingly overnight - Help

[Tartufo]

We've had two tanks up for a few months, and they were doing beautifully. We set them up as we do our freshwater, with old media, cycled rocks, live sand (marine tanks only), and Fritz Turbo. We dose with ammonia twice, and once those cycle, we add fish. Our various snails kept the algae at bay. The only concerning issue we saw was hair algae, but hermit crabs quickly took care of that.

Fast forward a few months and we added some marine cultured rock. Within a week of them being in the tank we are seeing algae everywhere, in one tank, and our cuc isn't doing much. One picture shows it. Another picture has something that is growing on the rock in question. Is it something that I should fear/deal with? If so, how? I see hairs sticking up from the sand today. They are brown, so I doubt it is hair algae. Maybe it is more debris from the sand.

The pictures were taken with the lights on, but through an orange lens, if that matters.

This is a 25 AIO with the following parameters. We do 5-10 gallon water changes each week or maybe twice every other week. We have a rack of coral out of the picture, so I need to keep the lights on.

Ammonia: 0
Nitrite: 0
Nitrate: 20
PH: 8.0
Calcium: 375
Alkalinity: 12.5
Phosphate 0
Magnesium: 1,140

 

[Mr. Mojo Rising]

How many fish in the tank? How much do you feed? What is your filtration like? Do you have any powerheads in the tank, how do you move water? What kind of test kits are you using? You are doing large weekly water changes, but 20 nitrates to me is high, what is keeping the nitrate that high?

 

[Tartufo]

How many fish in the tank? How much do you feed? What is your filtration like? Do you have any powerheads in the tank, how do you move water? What kind of test kits are you using? You are doing large weekly water changes, but 20 nitrates to me is high, what is keeping the nitrate that high?

How many fish in the tank? - 2 (Yellow Line Goby and Royal Gramma)
How much do you feed? - Once a day, about 1/3rd of a block of shrimp, maybe up to 1/2 some days.
What is your filtration like? Two media baskets with filter floss and carbon
Do you have any powerheads in the tank, how do you move water? We have one that sends flow from the back right corner to the front left. It is a controlled powerhead.
What kind of test kits are you using? The kits vary depending on the test. Either API, Hanna, or Salifert
You are doing large weekly water changes, but 20 nitrates to me is high, what is keeping the nitrate that high? I don't know other than overfeeding. We use boxed water or stuff we make using RODI water. Some weeks we see a level of 10 and some are 20. This past week was 20.

 

[Mr. Mojo Rising]

I think you are slightly overfeeding, a half or even a third of a cube is too much for 2 nano fish. I would suggest to use your third and keep it in a cup in the fridge and feed that third over 2 or 3 feedings per day, not all at once. Those nano fish will eat 3-4-5 pieces each and the rest rot. Not sure about your clean up crew but you should have a few hermits and nassarius snails and bumble bee snails to eat up any leftover food. Also get some algae grazing snails like turbo snails. Shrimps help too and add to the aesthetics. With that said, you are not crazy overfeeding IMO, just slightly more than I would.

Not sure how often you clean out your filter floss, but it should be every few days, don't leave it too long as they become the so-called nitrate factories.

Also keep in mind that a 3 month old tank is now smack in the middle of the "ugly stages", what you are facing is very normal, we all go through it. It will take another several months for the tank to stabilize, in the meantime I would keep up with your habits, you seem to be on top of everything.

Honestly your tank really doesn't look any worse than it should, it looks exactly like a 3 month old tank started with dry rock should look, so don't get discouraged.

If you are interested in corals, I would start adding easy corals now. Each coral comes packed with loads of different bacteria's and biodiversity, add corals from different sources, different tanks. You can also add some copepods.

Good luck

 

[W31Olds]

When you added the marine cultured rock did you cure it for a period? The live rock is great stuff, but a lot of the live organisms will die off in the first few weeks adding to the nutrient levels of your tank causing Algae problems. I just received 40lbs. of TBS Rock and things seem to die every day and it did raise Nitrates in my holding Tank. The algae doesn't seem to grow on the Live Rock but the will go on the Dry Rock.