Seperating alga from water

[Suzy]

Is it possible to separate the cells in my phytoplankton cultures without killing them? I mean, in a home/ hobbyist setting? I am never sure all the fertilizer is used up, and I feel nervous adding it to my newborn fry nurseries.

[JimWelsh]

I don't know about separating the algae cells, but I can tell you that F/2 media has about 55 PPM of Nitrate to start with (Math below). Let's assume that your phyto culture consumes only 90% of the fertilizer, then that means your phyto culture has only 5.5 PPM of Nitrate left over. Take that, and then dilute it in the fry tank, and I don't think you have a lot to worry about. You could always test your phyto culture for Nitrates.

Per the CCMP site, Guillard's F/2 media has 1.0 ml/L of a stock solution that has 75 g/L of Sodium Nitrate. The Sodium Nitrate has a molecular mass of 84.9949. The Nitrate ion has a molecular mass of 62.0049. So, 62.0049 / 84.9949 of the 75 g is Nitrate. That means that the amount of Nitrate in fresh F/2 Media is 75 * (62.0049/84.9949) / 1000 / 1000 = 0.0000547, which is 54.7 PPM.

[Suzy]

Thank you for the quick reply! That is very kind of you!

I had not thought of testing for nitrates. I guess I could assume that if the nitrates are used up, the copper and other heavy metals would be too? I could feel more comfortable ( maybe!) if I were only thinking of raising fish but delicate inverts? It is just trial and error, I guess.

I am asking because I took an online class about spawning invertebrates and I do so want to be a Invertebrate Embryologist when I grow up!

[BaboonScience]

For relatively small volumes of algae (several liters or say a gallon), you can try placing the bottle into the refrigerator. In about 24 hours most should settle out. You can then pour off most of the water, leaving a concentrated algae that can be dosed into the system. This is something that you can experiment with.
John

[Suzy]

Thanks! I will try this, and see what I come up with. I still wonder how DTs does it.....

[Scottt]

Most commercial algae concentrates are centrifuged. I'd recommend not worrying about the nitrates in the live phyto. It is common and successful practice to use it as a greenwater without concentrating it.

[BaboonScience]

Most commercial algae concentrates are centrifuged. I'd recommend not worrying about the nitrates in the live phyto. It is common and successful practice to use it as a greenwater without concentrating it.

That is correct. They are called continuous centrifuges and smaller non-commercial units do exist but are quite expensive. While I do posses a unit that was purchased through WildCo, I currently use a home made unit that is more efficient for my needs.
While these units are useful in concentrating algae, even to a paste, they are not necessary for the greenwater methods commonly used for larval fish rearing. In fact the live algae are quite useful in sequestering nitrogenous waste and converting it to plant mater. The algae are then consumed by the rotifers. Thus the dual purpose of green water. Mediating waste in the larval tank and supplementing the available food supply.

[Suzy]

Thanks, guys. I really appreciate your responses.

I won't worry about it until I get some really cool animal spawnage! I volunteer at our local aquarium, and a few weeks ago I saw a funky huge black urchin spew out a huge cloud of something. I waited for 2 hours to see if his tankmate would respond in kind, but alas, no.....

[enigma]

We have found very minor traces of fertilizer making it through a properly grown out culture. However, these are so small as to be virtually nil. If you do want to separate, Dr. John "Lauth Baboonscince" has some pretty neat box fan centrifuge schematics. If you ask nicely via PM I'll bet he'll share them.

Otherwise, you'll be dropping $7-15K for a nice continuous flow centrifuge.

[seafarm]

I wish my centrifuges were only $15K. Mine run from $45K to $100K, but they have 4-6 foot bowls

[BaboonScience]

I wish my centrifuges were only $15K. Mine run from $45K to $100K, but they have 4-6 foot bowls

Yes, but you are using the big guys!
6 foot bowls, holy cow! What rpm do they run at? At that diameter, the G forces add up quickly.
I don't think that the little lab jobs would help you too much. And those little jobs are quite costly as well, considering what they do.
John

[seafarm]

I think the really big systems that harvest Nanno push over 6,000 G's. We harvest over a 1/2 million gallons of Nanno on a good day so they are designed for very high flow through, but without breaking the cells.

[BaboonScience]

I think the really big systems that harvest Nanno push over 6,000 G's. We harvest over a 1/2 million gallons of Nanno on a good day so they are designed for very high flow through, but without breaking the cells.

Nano cells are tough, they can take the high G force. But 6K is pretty astounding. However, I know that my lab toys often pass a certain percentage of the nano if the flow rate is too high. I can understand the need for speed.
By the way folks, that is tens of thousands of gallons an hour!

[rsman]

I think the really big systems that harvest Nanno push over 6,000 G's. We harvest over a 1/2 million gallons of Nanno on a good day so they are designed for very high flow through, but without breaking the cells.

Thats it?

darn, I was hoping to be impressed

[sunny d polyp]

Hope someone answers this; what do you do with the left over culture water? I am culturing phyto and copes and live in a subdivision, I use the fridge method of concentrating the phyto specifically Tet and don't know what to do with the left over culture water, I have a septic tank so I don't flush it in fear of upsetting the fauna (fresh and salt) (maybe it doesn't matter?) I'm designing a system for phyto using 7.5 liter bags (20) and will ramp up the roti's which will increase the waste water and I'm not sure how to keep from just dumping it it the yard. How do you deal with it or do I even need to worry about it?

[sunny d polyp]

Guess I'll give myself a BUMP!

[johnrt]

Hope someone answers this; what do you do with the left over culture water?

I separate the algae from water by feeding the algae to something bigger that can eat it and then feeding the 'bigger something' to something else, which hopefully I sell to keep the wheel spinning. After all, filter feeders are great at filtering.

I then recover the 'algae water', by filtration through a 53 um screen to remove the big things I am feeding the algae to: rotifers; brine shrimp; copepods and etc, and dump the 'algae water' into a large filter/storage tank. It then runs through a sand filter multiple times to clarify. The rotifers et al go to 'something else'.

Then batches of cleared 'algae water' are transferred to a circulating cleaning 55 gal drum, where the chemistry and salinity is adjusted to f2 levels, passed through a 5 um filter and a UV sterilizer multiple times until it gets pumped back into the algae tank. By this point it is downright sparkely and clear. Add some light and it gets all green again.

Why throw it out?

[sunny d polyp]

Thanks for your reply, 5 um screen, how do you keep the screen from clogging is it pressurized? Do you have any pics of your set up? I've been raising rots and phyto on a small scale and getting ready to ramp up after I research thoroughly.

[johnrt]

Thanks for your reply, 5 um screen, how do you keep the screen from clogging is it pressurized? Do you have any pics of your set up? I've been raising rots and phyto on a small scale and getting ready to ramp up after I research thoroughly.

The 5 um filter we use is a 10" depth filter like you would use on the front end of an RO/DI unit. There are no pictures, so here goes 1000 words (well 1900, more or less. It would have been two pictures.).

Disclaimer:
This is what I have done and I am happy. If you want to do something similar, that is your choice, but remember, we will be mixing a witch's brew of salt water, electricity, pipes and hoses under pressure and you may be installing it in a building you rent or may not yet fully own and your spouse might not be amused when something unexpected happens. I have no connection with the recommended suppliers, they are just who I use and I know you can get the needed stuff there. Other products might be better or cheaper.

*I know I will be asked, 'Why Bluetooth Walrus?'. It looked a little like, well a very little like, a Walrus at one point in it's development and 'Bluetooth' is a nod and a wink to The Big Bang Theory. That is the official story and I will stick to it.

The Bluetooth Walrus consists of two parts: the water holding/clarifying tank and the sterilizing drum.

Things to assemble:

Holding/Clarifying Tank

1 x 100 gal plus, water storage thing (You want the bulk of the crud to settle out here so you will need to be able to remove settled crud easily or it will never get done. Right?): Old ugly tanks, cattle troughs, children's wading pools (remove children as they tend to keep the crud in suspension). . .
1 x 3/4” barb 'T' (Home Depot/Lowe's)
2 x 3/4” ball valves and whatever fixins you will need to attach them to the 3/4” garden hose (Home Depot/Lowe's)
1 x bunch x 3/4” hose clamps for use on all dry hose/barb junctions (Home Depot/Lowe's)
1 x WAYNE-Pond-Bio-Filter (http://www.grandcloseouts.com/servlet/t ... ter/Detail)

The WAYNE-Pond-Bio-Filter is a cheap knockoff of the cheap Tetra PF Series Koi pond Bio-Filters, so don't expect much, but at $23, it's cheap. Chuck out the useless Bio-ball things, wrap the foam filter around the outlet tube and 2/3 fill the bucket with coarse aragonite sand. Mount the sand filter above the water storage thing you are using so that when the sand-filter chokes up, it will overflow into the storage thing. Cut any metallic fitting off of the hose. We will not be using them. Toxic. Hook the pump to the filter according to the instructions that come with the filter, with the following modification:

You will want to use the pump to feed the filter at a low flow rate yet allow you to also use it to transfer 35 – 50 gallons of water to the sterilizer fairly quickly. To do this, cut the hose leading from the pump to the filter and install the 'T' barb. Connect a ball valve to both arms of the 'T'. Now reconnect the hose that goes to the filter to one of the ball valves. This will be the low flow sand-filter arm of the 'T'. Connect a longer section of hose, that is long enough to reach the sterilizer unit, to the second ball valve. This will be the high flow return/delivery hose. In normal operation, the low flow ball valve to the filter is only partly opened to supply a slow flow to the filter and the ball valve on the long high flow section of return/delivery hose is partly closed to provide back-pressure and the end of that hose returns to the storage thing. The ideal setting for the valves is such that there will be some liquid above the sand bed in the filter, but not enough to cause an overflow. When you want to fill the sterilizer unit, fully close the filter valve and open the storage valve, with the end of the long return/delivery hose in the 55 gal drum. Do not walk away. Remember: 100 gallon tank is now feeding a partly full 55 gallon drum. . .

The holding tank is fed dirty water that is the result of siphoning the bottoms of zooplankton (brine scrimp, rotifers and copepod) cultures. I do not expect the sand filter to be able to digest the 'heavies' in the zooplankton waste, so I remove it. If you build some baffles into your water holding thing, you can concentrate the grunge that settles out into one main area for cleaning. The sand-filter will work poorly for the first week or so, but once there is a good bacterial colonization of the sand, it will strip out very small particles, such as Nannochloropsis (2 – 4 um) from a tub full of water in a couple of hours. Consequently, the water you transfer to the sterilizer will be very clear.

Sterilizer Drum

1 x 55 gal plastic drum with a clamp or screw on lid (you can find used pickle barrels in most cities)
1 x 1 1/4" saw drill hole cutter for an electric drill (Home Depot/Lowe's)
3 x 1/2” UniSeals (Bulk Reef Supply. I am beginning to warm to these things.)
1 x 3/4" UniSeals (Bulk Reef Supply)
1 foot or so x rigid 1/2" plastic water pipe or electrical conduit, suitable adhesive and whatever you can find that will attach the pipe to a 1/2” garden hose (Home Depot/Lowe's)
1 x 1/2” treaded 'T' barb (Home Depot/Lowe's)
3 x 1/2" ball valve and fittens to attach them to a 1/2” garden hose (Home Depot/Lowe's)
1 x length of 1/2" garden hose that is long enough to go from the sterilizer to you algae tanks (Home Depot/Lowe's)
4 x shorter lengths of 1/2" hose to connect the pump, depth filter, 'T' barb and UV unit together
1 x bunch x 1/2” hose clamps for use on all dry hose/barb junctions (Home Depot/Lowe's)
1 x 1,000 - 1,800 gal/hour submersible pump with 1/2” fittings (LFS or kicking around the basement)
1 x replacement electrical plug, either two or tree pronged depending on the style on the pump you have chosen. We will be replacing that plug (Home Depot/Lowe's)
1 x RO unit filter pressure housing with 1/2” ports (Bulk Reef Supply)
2 x treaded 1/2” barb adapters (Home Depot/Lowe's)
several x 5 um or 1 um depth filters (Bulk Reef Supply)
1 x 15W Aqua-Step Ultraviolet Sterilizer (http://jehmco.com/html/uv_sterilizers.html) Good product, good price.
2 x 3/4” treaded to 1/2” barb adapters (Home Depot/Lowe's)
1 x bottle or bulk pack f/2 chemicals (Florida Aqua Farms)
1 x A whole lot of experience in fitting things together in a way never imagined by the manufacturer and which voids warranties, alarms mortgage holders and insurance brokers, yet does not leak too much.

To get started, drill 4 x 1 1/4" holes near the top of the drum, above the projected water-line, and insert 3 x 1/2" and 1 x 3/4" UniSeals. For the first three, choose the UniSeals size such that you can jam your 1/2" garden hose through it and the third should be 3/4”, which will hold a 1/2” pipe loosely.

The 15W Aqua-Step Ultraviolet Sterilizer is rated at 450 g/h but I run it much slower. I'm not satisfied with just killing the beasties. I want to vaporize them. So I throttle the flow back to about 150 – 200 g/h. To do this I use a flow control setup like the one on the storage/clarifying tank. The design is such that the water flow goes from the pump at the bottom of the drum through a 1/2” UniSeal at the top of the drum and then through the 1 or 5 um filter. The outlet from the depth filter is connected to a 'T' barb, with the low flow arm, controlled by a ball valve, going to the UV unit and the higher flow arm, also controlled by a ball valve, returning to the drum through one of the 1/2" UniSeals. The outlet from the UV unit is connected to the long hose that you will use to fill algae tanks. The end of this hose also has a ball valve and a small section of pipe so that you can turn off the flow temporarily while moving to the algae tanks or between them.

When designing the end of the delivery hose, I was trying to emulate a gasoline nozzle you find at a service station. You may want to add some elbows so that you can 'hook' the delivery hose onto your algae tanks while filling. That is not an excuse to walk away. See above. The same 'hook' can be inserted loosely into the 3/4” UniSeal at the top of the drum while the water circulates. In normal operation, this valve is always open so that the UV unit does not overheat and so that there is never stagnant water in the hose growin' greebies.

Attach the depth filter and the UV unit to the outside of the drum. Use Duct-tape, old bicycle inner tubes, laces off rusty skates and the like or just let them rattle around at the base of the drum. (Hence no pictures.)

Now we have a pump in the bottom of a 55 gal drum with a screw on lid, yet we need to get power to the pump. To do this, cut the plug off pump power line and tread the wire through the last 1/2” UniSeal. Now wire the replacement electrical plug onto the pump cord. Get the polarity right. Please. Check it. Make sure. You are choosing to do this. No pressure.

In operation, Fill the drum with cleared water from the holding/clarifying tank and allow it to circulate for a while to mix with any existing contents. Take a 6 oz. sample and test for pH, salinity, nitrate, phosphate, calcium, alkalinity and magnesium. Do the math, add the dosage to get the water right, and add f/2 concentrate. Open the UV supply valve partly and the delivery nozzle valve fully and insert the nozzle loosely into the 3/4” UniSeal. Partly close the high flow return valve to provide back-pressure and adjust so that the flow through the UV unit is between 150 and 200 gal/h. You can time the filling of a 5 gal bucket located at the same hight as the waterline of the drum. At 150 gal/h, it should take 2 minutes to fill a 5 gallon bucket.

Allow the water to circulate for several hours (overnight) before use. When you want to deliver water to the algae tanks, shut off the high flow return valve, temporary close the nozzle valve and fully open the low flow valve and carry the nozzle over to your algae tanks and fill.

Since the water is thoroughly 'cooked' in the sterilizer, you can use the same water for different algae cultures. I grow Nanno. Tetraselmis and T-Iso, and feed the holding tank with waste brine shrimp, rotifer and copepod water, without cross contamination and I throw out very little water. When the sand filter is running correctly, you will be pleasantly surprised how long the depth filters last. My Bluetooth Walrus has been running for 6 months and I have yet to notice a pressure drop that would indicate that I should be changing the 5 um depth filter.

[jadeguppy]

johnrt, where are the pictures!

[johnrt]

johnrt, where are the pictures! ;)

There are no pictures. You get the 2000 words. Cameras capture souls. Well no, but they stifle imagination. Read my words then do your thing. ;-)

John T

[sunny d polyp]

Johnrt, you are my hero, thank you!

[johnrt]

Johnrt, you are my hero, thank you!

It's just a bunch of words. I hope I got them in the right order. . . Thanx.

[Mouseinhat]

Most helpful, better than photos, as I now have my own pictures in my head.
Thanks.

[johnrt]

Most helpful, better than photos, as I now have my own pictures in my head.

The beauty of pictures in your head, is that they tend to be made of stuff you have seen and can get.

Tell us about, don't show us, your improvements. John T