Colour of Live Rocks

[Yang Kevin]

I bought some live rocks and like them because of the purple "algae" growing on them.

With time, the purple "algae" seems to go off and my rock becomes normal grey tone.

How does one keep the purple "algae" growing healthily?

[Gouldian]

I bought some live rocks and like them because of the purple "algae" growing on them.

With time, the purple "algae" seems to go off and my rock becomes normal grey tone.

How does one keep the purple "algae" growing healthily?

The purple algae are coraline algae. From your descriptions, they are dying off, due to:

• Water parameters - low in mg, kH and Ca or high NO3 and PO4
  
• Drastic change in lighting, sudden drastic change in lighting will cause temporary die-off
  
• Predators - some urchin and snails feeds on them but will never cause the problems you mentioned above
  

Ensure your water and lighting parameters are stable and they will re-established on your LRs again.

[Yang Kevin]

All my fishes, anemones, etc are very healthy. Does that equate that the water parameters are balanced and good? or perhaps the other occupants are more hardy than the coraline algae.

Thanks for your inputs, will however check the water parameters again.

[kira76]

You need to chek your Ca, Mg and kH. The basic parameter for corals (esp SPS) and coraline algae.

[jxlex]

Hope this might help (stolen off marinedepot):

Thanks for the question. It’s funny that you should ask that question. Many of my friends have so much coralline, that you can’t even see the pumps!

Coralline algae is surprisingly easy to grow, and if taken good care of, can grow relatively fast in FOWLR tanks (fish only with live rock). How? Well, let’s look at the things that really effect coralline algae growth.

In terms of water chemistry, coralline requires only a few things different than your fish do. Like corals, they require calcium, magnesium, and some source of carbonate (alkalinity). So keep your parameters stable and in line using good calcium, alkalinity, and magnesium buffers. Keep your chemical parameters as follows:

Calcium: 380-450 ppm

Alkalinity: 2.8-4.3 meq/L, or 8-12 DKH

pH: 8.1-8.3

Magnesium: 1200-1400 ppm.

Also, keep your nutrient levels relatively low. High levels of phosphate are detrimental to coralline algae growth in two ways. First, there is anecdotal evidence that low levels of phosphate are directly inhibitory to coralline algae growth. Second, phosphate contributes to the growth of competing algae, such as hair algae. That algae competes for space, light, and nutrients with the coralline, and even grows directly on top of it. Other algae, such as diatom algae and cyanobacteria, also compete for space and light, so keep your silicates, nitrates and other problem nutrients low.

Surprisingly, many species of coralline algae actually prefer low to moderate light. In many very dimly lit tanks, coralline algae completely overtakes rocks, pumps, and even the back glass. If you have moderate to low lighting, moderate to low light coralline algae species will dominate your tank. So moderate power compact lighting, or VHO lighting should work great for you in a FOWLR tank.

If it’s still hard for you to grow algae, there are a couple tips and tricks that you can consider. First, try purchasing new liverock from an already established tank. Many fish stores will have older rocks that are completely covered in coralline algae, that they will not mind selling at a premium. Just buy a few pounds, since the algae will spread. Seeding your tank with a variety of coralline algae species will allow you to introduce a species of coralline to your tank that may be better suited for your lighting and water chemistry. Second, if you do have some coralline algae, try taking a new, washed, firm toothbrush, and gently scrape the algae until a light dusting of it come off. Supposedly, this encourages the spread and colonization of coralline algae spore. If your tank is currently running ozone or UV sterilization, turn it off for a while, as you may be hindering this spread and colonization of coralline algae spore.

If all else fails, there is anecdotal evidence that some amino acid supplements can help to encourage coralline algae growth. The effects are purely anecdotal, but the idea is promising.

Try any or all of the things above, but don’t expect to see results right away. Coralline algae grows relatively slow compared to nuisance algae. Expect to see results in 2-3 months, rather than 2-3 weeks.

Have fun!

[Yang Kevin]

Very informative . Thank you for sharing the above info.

[teresaswan]

This is really fantastic post, thank you so much

Funny SMS

[andythiam]

me still learning. nice info

[jai9prakash@yahoo.com]

Good topic..I enjoyed reading it

[exomanor]

great info thx