Plankton Culture & Feeding

[Entomophage]

I've got a new system in the works, and I'm interested in learning more about culturing plankton (and other live foods) to feed my reef.

I'd like to simulate natural feeding conditions for inverts and fish as closely as possible, and it seems the best approach would be to culture phyto -> zooplankton cultures, as well as larger food organisms like pods. Additionally, I'd like to automate a dosing system to introduce food organisms to my reef on a steady, continual basis.

What are the pitfalls of dosing culture water straight to the reef? I imagine the culture medium itself is fairly high in nutrients, but is this significant in the volume we're talking about? What about trapping and moving pods from my refugium to the display? Has anyone experimented with a pod trap connected to a dosing pump?

The end result I have in mind would basically be a high nutrient import system which would need to be balanced by equally high exports. Heavy skimming would almost certainly work against the goal of keeping microscopic food organisms suspended in the water column, but perhaps with a combination of a refugium, ATS and skimming (periodic skimming on a schedule opposite plankton feedings?) a balance could be maintained.

I'm excited to hear of other's experience with this, or if a purely live-food reef has ever been attempted. There's an article by Eric Borneman ( http://www.reefkeeping.com/issues/2002-07/eb/index.php) in which he quotes Dr. Ron Shimek as saying the food availability in a wild reef would translate to feeding 250-350 mL of wet food per 100g daily. How close can the hobbyist get to balancing this level of import/export?

 

[SantaMonica]

Your ability to feed will be in direct proportion to your ability to remove N and P.

When trying to replicate the food and filtering levels of the ocean or lakes, you need to think of your tank as invisible in the chain, meaning, it is a small bump on the nutrient road. The majority of nutrients are Food In ==> Nutrients Out. The amount of food that your corals consume from this pathway is not very significant.

Feeding is easy. So start working on your filtering, which is not yet at a level where a hobbyist can compare to an ocean. Once you figure how much you can filter, then you can see how much you can feed. Thati is, if you can afford all the food

 

[Entomophage]

Hey, thanks for the reply!

Is there any reliable way to quantify my nutrient export before I start dosing phyto/zoo? Maybe I should track the volume of material being exported through skimming and pulling macro from the fuge and use this as an upper limit of the input.

My working plan is to run a skimmer that's rated significantly above the volume of my system (I've got around 200 gallons total, so maybe one rated for 500?), but on an opposite schedule from feedings. Combined with aggressively propagating macro in the fuge and running an ATS, I'm hoping I'll have enough overhead for significant import via life foods.

Any other thoughts on the matter out there?

 

[SantaMonica]

A skimmer is not exporting any nutrients, only food. The more a skimmer runs, the more food is exported, but the level of N and P stay the same. If you leave the food in your system, is it assumed that your livestock will consume it all because the levels are still far below natural reefs.

As for measuring algal export, you can start by looking at screen size:

An example vertical upflow or waterfall screen size is 3 X 4 inches = 12 square inches of screen (7.5 X 10 cm = 75 sq cm) with a total of 12 real watts (not equivalent) of fluorescent light for 18 hours a day. If all 12 watts are on one side, it is a 1-sided screen. If 6 watts are on each side, it is a 2-sided screen, but the total is still 12 watts for 18 hours a day. This screen size and wattage should be able to handle the following amounts of daily feeding:

1 frozen cube per day (2-sided screen), or
1/2 frozen cube per day (1-sided screen), or
10 pinches of flake food per day (2-sided screen), or
5 pinches of flake food per day (1-sided screen), or
10 square inches (60 sq cm) of nori per day (2-sided screen), or
5 square inches (30 sq cm) of nori per day (1-sided screen), or
0.1 dry ounce (2.8 grams) of pellet food per day (2-sided screen), or
0.05 dry ounce (1.4 grams) of pellet food per day (1-sided screen)

If the lights are LED, cut the wattage in half.