<a href=showthread.php?s=&postid=6573806#post6573806 target=_blank>Originally posted</a> by rickburdeniuk
What about intentionally introducing a macro algae in the sump as a competitor?
To be really effective, you would have to make growing conditions for algae more favorable in the sump than it is in the main display.
There are a couple of ways to do this:
1) Provide a nutrient source in the sump
This could be a sand bed or Miracle Mud, or anything else to trap detritus. Since the goal of bare-bottom tanks is to remove, rather than store and release, organic material, intentionally maintaining a nutrient source in the sump seems to be a bad idea.
This is one of the strikes against Cheato. It acts like a ball of filter fuzz, trapping detritus. When I was using Miracle Mud, I used to take balls of Cheato out of my sump and rinse them off. The rinse water was dark brown after I was done.
2) Make the lighting more favorable over the sump than the main display
Might work. Need something like a 250-watt DE 6,500K metal-halide bulb to beat the power of the 250-watt DE 10,000K bulbs over the main display. I have a hard time, however, justifying running a 250-watt light for 8+ hours a day just to grow algae.
And, since the algae in the main display are closer to a nutrient source (fish food and fish poop), theyââ"šÂ¬Ã¢"žÂ¢d, probably, still out compete the algae in the sump anyway.
Youââ"šÂ¬Ã¢"žÂ¢d also have to choose an algae type for the sump that could do better in low-nutrient conditions than the rhodophytes. The standard ones, like Caulerpa and Cheato wouldnââ"šÂ¬Ã¢"žÂ¢t stand a chance. Halimeda would be a better choice, but again, it would have a tough time competing with algae in the main display because the algae in the main display would have a chance to get to the nutrients first.
I think a better bet is to try to introduce an acceptable algae type to the main display to out compete the nuisance ones for space. Or, get an herbivore that eats the nuisance algae.