Continuous vs 1x/day phyto feeding

[Formulator]

I have a couple cultures of phyto going and want to set up dosing pumps to make it a continuous culture. Would it be better to dose the tank with phyto and replenish the culture with fresh saltwater once per day in a larger amount or smaller amounts spread throughout the day/night? I was thinking I need to consider the impact to both culture viability and benefit to the tank. But I don’t know how either would be affected . Thanks in advance for guidance!

 

[DanyL]

I’ve been planning for ages to do a continued feed phyto culturing, in my case with a reactor within my sump because I need to utilize my chiller to keep temps down.

I have pretty much everything set it mind in my plan, except one thing - trace elements.

When you grow and harvest you allow the phyto enough time to consume the fertilizer, and even than some reefers report elevated traces found in their ICP test, because the fertilizers used often contain more than what your specific species consumes.

With a continues feed culturing however, you always need to replenish with seawater with added fertilizer to keep it going, and thus you always dose it into the tank together with the phyto.

So far, the only thing I come up with is to build my own fertilizer with the specific elements consumed by the species I plan to grow, and than through multiple ICP tests to dial down dosage of the excess trace elements found in the tank, so that the fertilizer excess would in fact be part of my tank’s trace element replenishment.

Thats a lot more work than I originally planned, so it’s been indefinitely stalled for now, and something you really want to take into account if you’re headed with that same path.

 

[Formulator]

I’ve been planning for ages to do a continued feed phyto culturing, in my case with a reactor within my sump because I need to utilize my chiller to keep temps down.

I have pretty much everything set it mind in my plan, except one thing - trace elements.

When you grow and harvest you allow the phyto enough time to consume the fertilizer, and even than some reefers report elevated traces found in their ICP test, because the fertilizers used often contain more than what your specific species consumes.

With a continues feed culturing however, you always need to replenish with seawater with added fertilizer to keep it going, and thus you always dose it into the tank together with the phyto.

So far, the only thing I come up with is to build my own fertilizer with the specific elements consumed by the species I plan to grow, and than through multiple ICP tests to dial down dosage of the excess trace elements found in the tank, so that the fertilizer excess would in fact be part of my tank’s trace element replenishment.

Thats a lot more work than I originally planned, so it’s been indefinitely stalled for now, and something you really want to take into account if you’re headed with that same path.

Dang I didn’t consider this… And I use reef moonshiners so really don’t want to throw a wrench in that… back to the drawing board I think. I assume the F/2 formula is public information, so I could at least calculate the worst-case impact to the tank chemistry if it were dosed at full strength right after adding fertilizer to the phyto culture.

 

[DanyL]

Yup.. it took me awhile to realize this too.

And yes, the F2 fertilizer is open source, and you can easily find what elements are required for a specific species to thrive by looking at various articles and research papers, enough to make a fair estimate of how this would work out, but it certainly needs quite a bit of exploring and obviously validation of and when it gets executed.

 

[Lavey29]

The ocean has a continual unlimited supply of phytoplankton so having a constant source makes sense but then again may not be the same result in our closed systems. I do hand dose phyto feast daily though in small amounts.