Phytoplankton do we actually need to dose?

geeked · Apr 3, 2023

This is my first post on R2R. long time follower but only recently created an account. Anyways, my question is; if copepods eat phytoplankton and maybe detritus, why would we need to dose phytoplankton? I have had my aquarium for 2 years but before that I've had multiple tanks and have been in the hobby off and on for 10 or so years. I have always had an abundance of pods without really trying to keep them. I never dosed phyto or anything else until this year. Pods seem to thrive in our aquariums so why do we need to dose extra phyto? Isn't it already abundant in our tanks and what's being pulled out of skimmers (along with other things)? I have noticed that some tanks without skimmers look green or brown which leads me to think that it isn't a bacteria bloom like others may assume but an abundance of phytoplankton.

blaxsun · Apr 3, 2023

Because < insert product placement here >.

bushdoc · Apr 3, 2023

Phytoplankton is a good source of phosphate if your tank is deficient.......

MnFish1 · Apr 3, 2023

no you do not.

Kasrift · Apr 3, 2023

geeked said:
This is my first post on R2R. long time follower but only recently created an account. Anyways, my question is; if copepods eat phytoplankton and maybe detritus, why would we need to dose phytoplankton? I have had my aquarium for 2 years but before that I've had multiple tanks and have been in the hobby off and on for 10 or so years. I have always had an abundance of pods without really trying to keep them. I never dosed phyto or anything else until this year. Pods seem to thrive in our aquariums so why do we need to dose extra phyto? Isn't it already abundant in our tanks and what's being pulled out of skimmers (along with other things)? I have noticed that some tanks without skimmers look green or brown which leads me to think that it isn't a bacteria bloom like others may assume but an abundance of phytoplankton.

The answer in my opinion (my opinion only with zero science to back this up) is that you are essentially just introducing more biodiversity.

Yes, you can have copepods without phyto, but that isn't the sole job of adding phyto. Phyto can help stimulate feeding responses in finicky corals or small mouthed corals like goni or even tridacna clams, it can feed a host of different types and sizes of copepods, can add phosphates or to some claims lower nutrients since phyto consumes nutrients (when you culture it you feed it nitrates and phosphates).

There are multiple reasons why, but I don't think you have to. As mentioned, marketing plays a portion, but many reefers play by the "keep it simple" playbook and enjoy just as much success.

Jay'sReefBugs · Apr 4, 2023

You theatrically don't have to do anything. Phyto just adds benefits to your reef system but it's certainly not a must . And no phytoplankton is NOT abundant in your reef system you can pull a sample under a microscope to confirm. Filtration these days along with reef tank conditions aren't optional for phytoplankton to thrive and reproduce you would essentially need to sterilize your reef system. The green tanks you see are more then likely green cyano ( synechococcus) often confused with green water and Nannochloropsis.