What is this on my rock

[Charlie G]

Hello. I was doing a water change to my DT and while pump was off and water still was able to take a good look at my rock. There is some coraline algae on my rock but just noticed this reddish-brown (rust looking) spots on my rock as well. Not sure how long it’s been there. Not sure what it is or if there is any reason for concern.

Hope you can help identify and advise.

It’s a 32g Biocube. It’s been up for exactly one year. Parameters have been stable with nitrate around 4.7 and phos 0.22. Do have some GHA but the few coral I have look healthy. I have 2 clowns and a Royal gramma. I usually do water changes weekly but wanted to see if I can wait two weeks and did one today (2 weeks after the last). That being said I did measure my nitrate and phos yesterday and they did go up to 7.7 and 0.28 respectively. Below are a couple of pics. Substrate looks fine.

Thanks in advance.

 

[stoney7713]

Cyno spots. Brush it off and increase water circulation if you can.

 

[Charlie G]

Cyno spots. Brush it off and increase water circulation if you can.

Will do. I did try to lightly brush but didn’t come off. Would Cyano come off easily?

 

[fishface NJ]

Yes cyano would come off easily if you brushed it

 

[DanyL]

Will do. I did try to lightly brush but didn’t come off. Would Cyano come off easily?

It usually is, but sometimes it'll get into the tiny spots in the rocks making it more difficult to reach using a brush.
Try to blow it off using a turkey buster, it usually works better for me.

Cyano usually appears when there is an imbalance between your nitrates and phosphates.
The recommended ratio is 1 to 100 - so if you have 10 no3 phosphate would be 0.1.
It's not a hard rule though, and you don't need to chase the exact numbers either, just make sure the ratio is somewhat around the numbers you'd expect.

0.28 PO4 is also considered a bit high, some reefers do keep their tanks around these numbers, however most prefer to keep it around 0.01 to and 0.1.

 

[Charlie G]

It usually is, but sometimes it'll get into the tiny spots in the rocks making it more difficult to reach using a brush.
Try to blow it off using a turkey buster, it usually works better for me.

Cyano usually appears when there is an imbalance between your nitrates and phosphates.
The recommended ratio is 1 to 100 - so if you have 10 no3 phosphate would be 0.1.
It's not a hard rule though, and you don't need to chase the exact numbers either, just make sure the ratio is somewhat around the numbers you'd expect.

0.28 PO4 is also considered a bit high, some reefers do keep their tanks around these numbers, however most prefer to keep it around 0.01 to and 0.1.

Agree with you with the phos. This is the first time this high (I tried to hold off 2 weeks to do a water change as opposed to by weekly) but for months has been consistently 0.22. I run mostly blue light and been feeding little (as far as I can determine) in order to keep GHA in check. I have been trying to avoid any chemical solution for nutrient control. Been relying on a vice as well as weekly water changes.

I did move my wavemaker yesterday (before I noticed this) it is closer to this area-maybe that will help. I have been reading that some add microbacter 7 to add competing bacteria.

 

[Charlie G]

Agree with you with the phos. This is the first time this high (I tried to hold off 2 weeks to do a water change as opposed to by weekly) but for months has been consistently 0.22. I run mostly blue light and been feeding little (as far as I can determine) in order to keep GHA in check. I have been trying to avoid any chemical solution for nutrient control. Been relying on a vice as well as weekly water changes.

I did move my wavemaker yesterday (before I noticed this) it is closer to this area-maybe that will help. I have been reading that some add microbacter 7 to add competing bacteria.

Meant to seat-been relying on weekly water changes and not over feeding.