My tank is 18 months old now, and by most measures thriving. About 2 months ago though, I started to get some what I thought was algae on the sand where it used to be white or coralline pink. The substance is green and brown and pretty smooth - sometimes with bubbles if I leave it too long. I've siphoned it off a few times but it comes back within days to a week. The other day I went full turkey baster on the whole sand bed and stirred it up really good and got a ton of stuff out. However a good bit of it came back within the day. This is when I started to suspect it might not be algae. I also notice that it does tend to reduce by ~80% when the lights go out which I believe is a dino thing? I'm wondering if I have dinos? This is almost exclusively on the sand too, maybe a little on some of the lower rocks but most of my rock is clean coralline covered. I also run a UV.
My tank is quite stable with good parameters:
Temp 78
PO4: .04-.06ppm
NO3: 3-5ppm
pH: 8.2 - 8.45
Ca: 450
Mg: 1350
Alk: 8.0
Would love any thoughts!
Day:
Night:
This is Cyano Bacteria. Cyano blooms typically start when water nutrient concentrations of phosphate, nitrate and other organic compounds are too high.
Some of the most common causes include:
- Protein skimmer which fills water with tiny air bubbles. As bubbles form from the reaction chamber, dissolved organic compound molecules stick to them. Foam forms at the surface of the water and is then transferred to a collection cup, where it rests as skimmate. When the protein skimmer does not output the best efficiency or you do not have the suitable protein skimmer to cover the tank, the air bubbles created by the skimmer might be insufficient. And this insufficiency of air bubbles can trigger the cyano to thrive.
- Overstocking / overfeeding, your aquarium with nutrients is often the culprit of a cyano bloom
- Adding live rock that isn’t completely cured which acts like a breeding ground for red slime algae
- If you don’t change your water with enough frequency, you’ll soon have a brightly colored red slime algae bloom. Regular water changes dilute nutrients that feed cyanobacteria and keeps your tank beautifully clear
- Using a water source with nitrates or phosphates is like rolling out the welcome mat for cyano. Tap water is an example
- Inadequate water flow, or movement, is a leading cause of cyano blooms. Slow moving water combined with excess dissolved nutrients is a recipe for pervasive red slime algae development
I recommend to reduce white light intensity or even turn them off for 3-5 days. Add liquid bacteria daily for a week during the day at 1.5ml per 10 gallons. Add Hydrogen peroxide at night at 1ml per 10 gallons. Add a pouch of chemipure Elite which will balance phos and nitrate and keep them in check.
After the 5 days, add a few snails such as cerith, margarita, astrea and nassarius plus 6-8 blue leg hermits to take control.
