Can a 65G aquarium sustain a continuous population of phytoplankton without nuisance algae?nce

dtruitt · Mar 4, 2020

I'd like to build up a self sufficient population of phytoplankton in my 65 to support a suitable pod population for two (or more!) dragonets.

We have chaeto in the refugium right now that is keeping the nitrate and phosphate at practically 0, regardless of how much we feed and how little we change the water.

Is it possible to maintain a continuous population of phytoplankton without removing the chaeto and or introducing so much additional nitrogen that it sparks a nuisance algae bloom?

CuzzA · Mar 5, 2020

If you have a skimmer it will remove the phyto. You can continuously dose phyto, but contrary to what you may think, it is likely that the phyto will bottom out your nitrates and phosphates as it will become the main algae in the system. This could lead to issues with corals not getting enough nutrients and potentially even dinoflagellates. It may also result in the death of your chaeto.

Personally I just dose an appropriate amount every evening when I have my filtration off and am feeding corals and fish.

dtruitt · Mar 5, 2020

CuzzA said:
If you have a skimmer it will remove the phyto. You can continuously dose phyto, but contrary to what you may think, it is likely that the phyto will bottom out your nitrates and phosphates as it will become the main algae in the system. This could lead to issues with corals not getting enough nutrients and potentially even dinoflagellates. It may also result in the death of your chaeto.

Personally I just dose an appropriate amount every evening when I have my filtration off and am feeding corals and fish.

The more research I do, the more I regret spending the money on a "good" skimmer. I have half a mind to pull the skimmer out and turn its compartment into another refugium.

How should I deal with nitrate and phosphate bottoming out? My cheato is already bottoming them out pretty well. Add fish and increase feeding until nitrate and phosphate are adequate to support the coral?

CuzzA · Mar 5, 2020

I'm not really sure of the best approach. You'll have some trial and error. For the sake of stability it may be wise to just culture the phyto and pods separately and replenish the tank. But before I did this I would weight the cost and time vs. Just buying pods from a company like rustalty.com and replenishing that way. You could also look into cultivating white or black worms or artemia. @Paul B has been keeping his breeding mandarins for years doing this. The problem with phyto is the cultures will eventually crash and you'll be producing so much you'll run out of space to store it. Of course you could then start selling it to local reefers. Lots of options, but again how much is your time worth.