CUC chemistry

[jarviz]

So i was just wondering about this cycle...when i feed my fish/corals, the uneaten food and their poop turns into nitrates/phosphates, that leads to algae. the CUC eats the algae/detritus, but then the CUC poops also.. that poop turns back to nitrates/phosphates and back to algae again. Isn't it just a never ending cycle?

So does a CUC really do anything besides keep the rocks/glass clean here and there? I do like that hermits and nasarrius's will dive onto uneaten food or a dying carcass, so that there isn't too much ammonia if something big dies.

 

[mdb_talon]

In large part yes they "just" recycle nutrients, but of course in doing so they help keep algae under control among other things. If using a protien skimmer a portion of their waste also does(or should with proper flow) end up getting exported via the skimmer before breaking down into nitrate/phosphate so their should be a net export of nutrients.

 

[ApoIsland]

So i was just wondering about this cycle...when i feed my fish/corals, the uneaten food and their poop turns into nitrates/phosphates, that leads to algae. the CUC eats the algae/detritus, but then the CUC poops also.. that poop turns back to nitrates/phosphates and back to algae again. Isn't it just a never ending cycle?

So does a CUC really do anything besides keep the rocks/glass clean here and there? I do like that hermits and nasarrius's will dive onto uneaten food or a dying carcass, so that there isn't too much ammonia if something big dies.

Invert waste is not nearly the same as fish waste. I fed a little red reef lobster and a giant hermit crab 100s of pellets per day. If I did 1/3 of that in my fish tank it would have crashed in a week.

 

[jarviz]

In large part yes they "just" recycle nutrients, but of course in doing so they help keep algae under control among other things. If using a protien skimmer a portion of their waste also does(or should with proper flow) end up getting exported via the skimmer before breaking down into nitrate/phosphate so their should be a net export of nutrients.

I guess that makes sense... that they are there for algae control... not really nutrient control.

 

[taricha]

right. A clean up crew is not a method of nutrient control.
it's an attempt at algae control.
To control nutrients in the algae, the simplest way is to export algae growth (scrubber, fuge etc)

 

[Randy Holmes-Farley Verified Community Expert]

FYI, it really doesn't matter if fish eat food or not. Most of the N and P in it ultimately in it ends up in the water.

Very little N and P is actually retained in the fish. Maybe none in an adult fish (since it is not growing). Same is true for people and most animals: they eat lots of food for the energy benefit. The N and P in that food is mostly excreted.

This give the data supporting that claim:

Aquarium Chemistry: Phosphate And Math: Yes You Need To Understand Both

Foods are by far the most important source of phosphate in most aquariums. In considering whether sources of phosphate other than foods are important, one must carefully look to the actual amounts involved to determine whether other sources are even worth trying to minimize.

reefs.com