This calculator will help you to determine how much feed your culture requires to produce the number of L-type rotifers you need to harvest each day. These feed rates will produce the same biomass (food value) of S rotifers, but the rotifer numbers will be about 2.5 times higher.
The traditional technique for growing and harvesting rotifers has been to count the rotifers and feed the culture based on the count. We recommend a very different technique–maintaining a constant harvest rate and regulating the growth of the rotifer population by regulating the amount of food you give them. This results in more stable and predictable rotifer production.
Rotifer egg production is high for only the first 3–5 days of their 7–15 day (depending on temperature) lifespan, so for the best production it is important to harvest at least 25% of your culture each day to keep your population young and reproducing vigorously. In a healthy culture the numbers of rotifers produced each day directly corresponds to the amount of feed you provide. If you need more rotifers, keep the same harvest rate and simply feed more to your culture each day; feed less if you need fewer rotifers. When you increase or decrease the feed it will take 1-3 days (depending on the magnitude of the change in feed rate) for the culture to reach a new equilibrium and stabilize production.
Note: Normally no ClorAm-X will be required when feeding RGcomplete, which contains ClorAm-X. With all feeds, actual ClorAm-X demand will depend on temperature as well as other factors. These recommended dosings will be adequate in most situations, but we recommend daily ammonia testing at least until a culture routine is established that maintains consistently low ammonia levels. Always use a salicylate-based ammonia test (turns green-blue) when using ClorAm-X.
- Compact Culture System™ (CCS)
- Rotifer Floss
- ClorAm-X ammonia and chlorine neutralizer
- Harvest Sieve
- Ice Cap dosing pump with built-in timer (for automated feeding of bucket-scale cultures)
- Tetra Whisper 10 Aquarium Air Pumps
- API Ammonia Test Kits
- Repeat Cycle Timer: Panda Timer or Minute Repeat Cycle Timer
Rotifers fall into two salinity categories - marine and freshwater. “Marine” rotifers are actually brackish water in origin and can survive and grow in salinity ranging from 4 ppt to 40 ppt.
There is much more information about culture of marine species, and they are therefore the preferred choice. The drawback is that rotifers grown in 20-30 ppt salinity are shocked when put into fresh water. They are not killed, but they may stop swimming for a time until they adjust to the lower salinity. But there is an easy solution - grow the marine rotifers at a lower salinity (15 ppt is actually the optimum). At 5 ppt marine rotifers such as Brachionus plicatilis will grow well, although they won't be quite as prolific. When the 5 ppt rotifers are put in fresh water (0 ppt) they will stop reproducing but remain healthy, alive, and will maintain their enrichment levels (for at least 1 hour).
To cultivate 5 ppt rotifers it is best to drop the salinity gradually, preferably lowering it no more than 10 ppt per day if you want to maintain production. While you are lowering the salinity the egg count and reproductive rate will be reduced, but once the rotifers have been at the target salinity for 48 hours they should rebound quickly. Always make sure that the ammonia (NH3) level is kept low (preferably less than 0.5) to avoid stressing the animals.