coralline algae or red slime algae?

Question

How can you tell the difference? This stuff is starting to cover the bottom of the tank. Kind of red / purple color, almost fuzzy or dusty looking & now bubbles starting to build up...

Very established 75 gallon reef tank.

Answer 1

Coralline algae is hard and typically grows of the live rock or glass. If this is something you can remove easily by scraping, it's red slime (which is actually a bacteria). There's a product you can find in stores called red slime remover, but I wouldn't suggest getting it - most of these products are antibiotics which will affect your biological filter. Instead, I'd go with other types of controls.

Since this is a bacteria, light levels don't have that much of an effect as they do for controlling algae. Your best options are to control water movement and nutrients in the tank. Red slime doesn't like to grow where ther's a lot of water movement, so you might need to add a powerhead to circulate the water a little more. Do you use tapwater for mixing salt? If so, this can be a source of nutrients (nitrate, phosphate) and you might want to switch to reverse osmosis water (available at self-serve "Culligan" dispensers for about $0.33/gallon once you buy the refillable containers). You might also try adding a phosphate adsorbing pad to your filter - you'll get some phosphates just from the food for the fish.

Not much will eat cyano, so snails and hermits crabs (cleanup crew) doesn't really help with this problem.

You can find a few suggestions in this link - it's written for freshwater, but the info also applys to saltwater tanks: http://www.skepticalaquarist.com/docs/algae/cyano.shtml

Answer 2

coralline algae is a tough, calcified algae, starts as small circles or patches and grows to a circle maybe 1" or so in diameter. oits its fuzzy/dusty or has bubbles, grows in sheets its nuiusance for the most part, sounds like you have a very thick growth of cynobacteria, try scooping as much out as possible and do weekly 10-15% water changes using RO water until you get it takne care of, you can also put thre lights on an 8 hours cycle and reduce feeding. RO water can be bought at walmart or target. you can cut thre lights down to 4 hours or cover the tank for a few days but alot of people get paranoid about it, one or two days at most, just remember coral are shipped in dark contaiiners for days and do just fine. but nutreint removal will work best in the long term, you can look into a refigium as well

Answer 3

Sounds like red slime algae/cyanobacteria.