Cyano Outbreak/Low Nutrients

[fishcore]

Hi! My 29 gallon is in its ugly stage right now, about three months old.

About two weeks ago or so, nitrate bottomed out, coming down from ~10ppm to 0. Phosphate has been 0 or near 0 as long as I've been measuring it, and only comes up when I feed my corals ReefRoids, to ~0.05ppm.

The nutrient imbalance has come with an outbreak of cyano (I think).

I've tried siphoning some of it out to give other micro organisms a chance to repopulate but with no nitrate in the water I don't think they're able to. These photos are post-cleaning, so it was slightly worse before.

Is this something that I should just leave alone to correct itself? Or do I need to dose potassium nitrate or something before it becomes more of a problem?

I've been running the protein skimmer for ~4h a day, let me know if I need to stop it completely. It was previously running 24/7 until I noticed the 0 nitrate.

I have three small fish in the tank and like 10 small inverts and feed 3 times a day, switching it up between frozen mysis, frozen brine shrimp, Reef Nutrition TDO Chroma Boost, and New Life Spectrum Grow. Only soft corals in the tank.

Thanks all!

 

[Mr. Mojo Rising]

All I would do for now is add another powerhead to get some better water movement, cyano oftens grows in low flow spots and that powerhead looks kind of small in your tank. I would add more flow and just ride it out for a while, see what happens

Seeing that your water surface is so flat I would run the skimmer full time to help oxygenate the water and get the dissolved organics out of the water. dissolved organics feed cyano and algae's.

Feeding 3 times a day and cyano growing tells me your water is not nutrient free. Just my 2 cents good luck

 

[fishcore]

All I would do for now is add another powerhead to get some better water movement, cyano oftens grows in low flow spots and that powerhead looks kind of small in your tank. I would add more flow and just ride it out for a while, see what happens

Seeing that your water surface is so flat I would run the skimmer full time to help oxygenate the water and get the dissolved organics out of the water. dissolved organics feed cyano and algae's.

Feeding 3 times a day and cyano growing tells me your water is not nutrient free. Just my 2 cents good luck

Awesome, thank you for the reply, I'll keep the skimmer running to help with oxygen.

It's hard to see, but there is another identical powerhead on the left behind the rock; should I point the right one at the surface for gas exchange and the left one at the sand bed to keep cyano off? Or should I point them at each other in an attempt to make turbulent flow?

 

[Mr. Mojo Rising]

Awesome, thank you for the reply, I'll keep the skimmer running to help with oxygen.

It's hard to see, but there is another identical powerhead on the left behind the rock; should I point the right one at the surface for gas exchange and the left one at the sand bed to keep cyano off? Or should I point them at each other in an attempt to make turbulent flow?

Ya sorry I could not see the second powerhead. I would point at least one of them up to the surface, more oxygenation is always good. But flow is one of the hardest parts of the reef tank, it really takes a lot of experimenting to get it right

 

[EnterName]

If you have a skimmer running the gas exchange at the surface becomes a bit less important. It certainly won't hurt like Mr. Mojo already said, but to get the flow right I would rather use it for something else. If you notice a biofilm forming at the surface that's something else, then you absolutely should get more surface agitation.

You have relatively coarse substrate so you can surely get quite a bit of flow in your tank without causing any issues

Manual removal might be something to take into consideration. Your tests will only measure NO₃ and PO₄, but there are also organics that contain nitrogen and phosphate and can be used through enzymes or specialized uptake paths of various organisms. In other words: you can't measure all the available nutrients in your tank so there might be much more available to those cyanos than your tests suggest.

 

[fishcore]

Ya sorry I could not see the second powerhead. I would point at least one of them up to the surface, more oxygenation is always good. But flow is one of the hardest parts of the reef tank, it really takes a lot of experimenting to get it right

All good! Just lets me know I hid it well

Flow has definitely been the hardest to get right, I feel like every time I adjust I just make it worse, LOL. I'm planning on getting an AI Nero 3 so I can at least have some variability/randomness in the flow, too. Thanks for the help!

 

[fishcore]

If you have a skimmer running the gas exchange at the surface becomes a bit less important. It certainly won't hurt like Mr. Mojo already said, but to get the flow right I would rather use it for something else. If you notice a biofilm forming at the surface that's something else, then you absolutely should get more surface agitation.

You have relatively coarse substrate so you can surely get quite a bit of flow in your tank without causing any issues

Manual removal might be something to take into consideration. Your tests will only measure NO₃ and PO₄, but there are also organics that contain nitrogen and phosphate and can be used through enzymes or specialized uptake paths of various organisms. In other words: you can't measure all the available nutrients in your tank so there might be much more available to those cyanos than your tests suggest.

Great to know that it's not just free floating nitrate and phosphate that keeps these guys fed. I'll watch a few videos and figure out how to create the most flow with my strange tank dimensions! And definitely keep the skimmer running too, thanks!