Outdoor Phyto & Zooplankton Culturing

R.Weller · Jun 12, 2020

Results are in. I probably should have made two different threads for phyto & zooplankton, but since we started one way, might as well keep going.

Here's the progression & development of the 180oz batch of phyto noted in the previous post.

There was an interesting development early in the cycle that was worth noting. We observed a few small bubbles on the algae in the post on 26-May. In our dense culture, this event was magnified for several days. It is observed again in the zooplankton tub from 11-June (see photo above). Someday this might be worth investigating why this happens for a certain density of phyto yet stops as the culture matures.

Here's a few pics of the culturing station mounted on the deck. We had some unseasonably hot weather with daytime temps in the 90's. We also had a few days of high winds. From day 4 on, we stirred the culture twice daily using a kitchen spatula.

Here are some comparsions when we pulled the culture earlier today. We used the remaining batch from Culture #3 on 05-June as the control. We brewed another batch indoors following the same methods outlined above to compare with the outdoor culture. Both samples developed for 8 days using the same 2:1 phyto to 1.021 RO + F2 .

We expected the outdoor culture to be more dense, but it appears that for this experiment, the indoor culture using constant temp (79 - 80 degF), constant airflow & synthetic lighting outperformed. However, given that the outdoor culture supports significantly more volume & has $0 economic impact, it is our prefered method.

As of today we have approx 250oz of live phytoplankton & the vast majority was cultured outdoors. We have run out of all previous 'dead' phyto stock, & are feeding the system 100ml of live, home cutlured, food daily. At this point, we have sufficient volume to test adjusting the ratio to 1:1 per the recommendation from Mercer. Our cost of $.56 / oz (19-May above) has now been reduced to $.11 / oz & continues to fall as we split the culture.

Hopefully we are as successful with the zooplankton culture as we have now been with phytoplankton, but I'm beginning to suspect that we might have to purchase a 16oz bottle of Pods as I did years ago & grow them into 3 gallons vs. using live rock from our refugium.

R.Weller · Jun 25, 2020

We've elected to shut down outdoor production of phyto because it simply makes more than we are able to consume or distribute. This certainly answers the question if it can be done with sunlight & wind.

In the meantime, we ran one more test with our indoor method for culturing using the recommended 1:1 RO saltwater to phyto vs. 2:1 as in all previous cultures. The results are visible below. The 1:1 is on the left compared with the 2:1 (labeled as the 'Indoor' sample from the previous post). The 1:1 is a little more dense, but it is not as significant as I had anticipated.

From the research, 2:1 seems like a good ratio when getting started with live cultures. However, the purpose is to add nutrition, which comes from the algae, so we plan to use the 1:1 formula going forward.

Once harvested, don't forget to keep it refrigerated & clearly labeled so children / visitors don't accidently taste something they are not expecting.

One final note on cost.

We sold 1 - 16oz bottle for $5 USD & produced another 60oz. From our original stock, we've produced over 300oz at a cost of $22. Our cost / oz is now around $.07 compared to $.56 when we started.

It's a successful & sustainable project.

R.Weller · Jul 11, 2020

On 27-June, I finally broke down & purchased a starter culture of copepods from another local hobbyist. After trying unsuccessfully for months to seed Pods from our refugium, I purchased x2 16oz bottles to jumpstart our community. I've had some of these rocks in our system for nearly 4 years, so it's a little surprising that there was insufficient population to get started, but it is a closed system, & we did have a Mandarian years ago before starving it (unknowingly to us). Having the right seed proved to be very successful with the phyto culture, so we had high expectations this would work.

One of the bottles we added directly to our refugium. It's a 50gal rubbermaid stock tank full of reef rock & two types of sand. There is plenty of algae & more amphipods & bristleworms than I can count. The other bottle we divided across two containers for further culturing.

One culture is a 16oz bottle mixed with 8 oz of tank water that we added a slow bubble to, & the other 8 oz, we mixed with the 2.5gal of phyto water from the 12-June post above that was designated for zooplankton. We added an airstone to this tank & dosed extra phyto when the Pods consumed everything that was grown outdoors. Both cultures have been successful & hopefully the results are visible in the videos below.

Setting up our phyto & zooplankton cultures has been a learning experience. We were successful with the right tools (seed in particular) & learnings that others have shared here on R2R. Indoor culturing seems to be considerably easier than outdoor, yet outdoor is great if you need significant volume. Going forward, it's great to have live food to feed the reef.

LBReefer · Aug 28, 2020

Following along. This is simply amazing.I love your scientific approach to it all.

You've inspired me to try and give it another go.

R.Weller · Aug 28, 2020

LBReefer said:
Following along. This is simply amazing.I love your scientific approach to it all.

You've inspired me to try and give it another go.

I'm glad to hear that you plan to try again. Certainly with the right knowledge & materials, the project is rather simple & the benefits to coral growth & overall nutrition are measureable for our system. I've shared some of that progress on our build thread.

It's been 6 weeks since the last update. We managed another 2gal from the original 16oz Mercer investment until it finally crashed. As far as I can tell, there must have been a contamination issue with the culturing vessels that I was using even though I washed with vinegar & RO between batches. The 64oz juice bottle did very well for the first few batches, but it started to thin as it matured until the point that the water would turn clear around the 4th day.

As I noted on 25-June, we moved everything indoors. The setup hasn't changed much since the post on 29-May, but I have made two changes. First, I switched to using a 64oz glass vessel instead of plastic. This should help prevent contamination. Second, I added rigid air tubing to help stir the culture at the bottom of the vessel.

This is a picture from earlier today when I split our latest batch. Unless something else changes, I don't plan to use the outdoor station as 64oz feeds our system for ~15 days & it only takes 7 - 8 days to grow. We restarted with another 1L bottle from Mercer, & after having done this for a few months, it's probably not a bad idea to plan on restarting the culture every 4 - 6 months from a reputable vendor to ensure quality. Considering the success that we have seen, spending a little $$ on Mercer enables them to continue to provide lab-quality live phyto to the community.

mav3rick478 · Sep 2, 2020

Totally agree that glad should help with contamination prevention. With most plastics being recycled nowadays it's hard to tell how long they will be good for before they start leaching.