Moving Bed & Algae Scrubber combo filter

[amwassil]

I have a 110 gallon stock tank with about 100 gallons of water for my three RES turtles. I originally had an Eheim Pro 3 - 2075 canister which worked well for several months and then started to leak around the hose connections in the filter head. I pulled the 2075 and put a Marineland C-220 and a Sicce Whale 120 on the tank while I figured out something permanent. That turned out to be a moving bed filter using 5 liters of Hel-x media in a 5 gallon pail. I later upgraded to a 10 gallon Brute plastic garbage can with 10 liters of Hel-x media. This filter is cycling fine and maintains the water very well. Except, a moving bed type filter is so efficient it creates an enormous amount of nitrates.

Of course, turtles don't breathe in the water, so a huge nitrate load is not detrimental to them as it would be to fish. However, my turtles didn't choose to spend their lives in a bucket of water in my apartment instead of a pond in the forest, so I want to provide them as pristine a habitat as I can. Hence, the search to find a way to eliminate the nitrates. I eventually discovered the algae scrubber!

So I am currently building a combination moving bed and algae scrubber filter in a 20 gallon Brute plastic garbage can. I have just completed the algae scrubber, using an
Expressions-LTD scrubber box and LED lights.

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The first photo is the cradle to support the algae scrubber box. The green ring was cut from a plastic planter that fit exactly onto the inner lip of the Brute can. I could not just hang the scrubber on the Brute lip because it would prevent the Brute lid from closing. The white cradle was made from PVC trim board glued with PVC pipe glue. The green rim and PVC cradle support the scrubber box to just clear the Brute lid.

The second photo is the scrubber box, with LEDs mounted, in the cradle.

The third photo is the plumbing for the scrubber box. The pump is a Lifeguard QuietOne 1200 (317 gph). I put a PVC union inline to facilitate removing the spraybar/waterfall for cleaning. The mesh is nylon sewing 'canvas' purchased at Walmart. It's 12"x6".

The fourth photo is the plumbing in the scrubber box, and the scrubber box in the Brute.

The next step is to cut (1) a hole in the bottom of the Brute for a 1" bulkhead to mount the incoming water jet; (2) a hole in the side of the Brute for a 2" Uniseal to mount the PVC pipe for the gravity outflow.

[SantaMonica]

Have not seen a turtle build in several years. I hope it works great.

[amwassil]

I purchased a set of wood end tables today at Sally Anne for $10 each. They are exactly the right size to fit in the space where the filter will go. I have the current 10 gallon filter on an adjustable metal shelf, but it just supports the weight marginally. So I decided to use something stronger. The tables will sit one on top of the other and I will have to modify the top table by cutting the legs to get the correct height for the bottom of the new filter and cut a 2" diameter hole for the water jet to enter the bottom of the Brute can. The pump will sit on the lower table. I'll post photos when I've got the tables modded.

[amwassil]

Well, the Sally Anne tables were a little too big! So I googled a bit and found a nightstand at IKEA that fit exactly in the available space. It looks nice, too:

http://www.ikea.com/ca/en/catalog/products/90121234/

I cut a hole in the top for the water jet to enter the Brute and removed the bottom and back of the drawer so I can pull it out of the way for access. I also built a base to raise the nightstand up about 4 inches.

I had to finalize the stand under the Brute, so I could then determine the exact location in the side of the Brute for the return pipe.

[amwassil]

The first hole I cut in the Brute was the bottom hole for the input pipe. I mounted a 1" standard bulkhead with a rubber seal on the inside. I decided to apply silicone glue on the outside under the nut. So I then had to wait a day to give the glue a chance to cure before doing anything else. The next day I cut a 3" diameter hole in the side of the Brute to mount the 2" return pipe in a Uniseal. I also decided to apply silicone glue under the flange of the Uniseal on the outside. So again, I had wait another day for that to cure.

So, finally, yesterday I was ready to start final assembly. First step was to remove the 10 gallon moving bed filter and supports and swap in the 20 gallon filter and the Hemnes nightstand. Second step was to disconnect the plumbing from the old filter and attach it to the new one. All I had to do basically was cut some 1" tubing to appropriate lengths. After finding a few small leaks and three attempts later here's the new moving bed filter in action:

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The black screen left of center is the top of the return pipe with a conical screen to prevent filter media from draining out of the filter. The spot in the center is upwelling water from the input jet at the bottom of the filter. Theoretically, the media sinks around the periphery and gets blown back up in the center flow of water. Interestingly, although this filter media has been cycling for about [three - correction: the oldest Hel-x has been in the water for nearly] 6 months already, it is still floating! It will only start to sink when the bacterial colonies on each piece of media reach critical mass. In the photo you can see media pieces of various colours. The darker the more bacteria is growing. The lightest pieces are those I added most recently, about two months ago.

So with the moving bed part of the filter working and free of leaks, next step was to mount the cradle for the algae scrubber:

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Next step, mount the algae scrubber box and its plumbing on the cradle. I connected the LED panels and the pump and everything worked:

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Here's the plumbing:

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Looks like I'm going to add another ring of plastic around the inside:

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[Added Jul11/15] One of the key features of a moving bed is enhanced oxygenation of the water. This is provided by injecting air into the input water flow. I neglected to post a photo of my air injection. I'm injecting air through two air hoses attached to the input pipe immediately above the cutoff valve with check valves (the small orange things in the photo).

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[amwassil]

As of this morning, water parameters are thus:

pH: 6.2
NH3/4: 0.0
NO2: 0.0
NO3: ~80+
PO3/4: ~0.5+

I'll connect the algae scrubber to a timer today and run the lights 12/12 for the first week or two. The water pump is on 24/7.

[Devaji108]

cool setup! but dont you think the ATS would the trick with out the "moving bed" ( 1st i have heard of that)
any way cool setup!!

[amwassil]

Devaji108

Theoretically, you are correct. It very well might! However, right now the moving bed is cycling and the algae scrubber is looking cool and pretty. That purple light glowing through the side of the plastic can looks particularly beautiful. Once the algae scrubber is established and has eaten all the nitrates and phosphates, if water params look close to pristine, I will probably take out the Hel-x and see what happens over the course of a few weeks. Turtles dump a huge organic load every day, so filtration changes have to be done slowly so as not to lose the cycle. I will certainly report my results here as this develops.

[amwassil]

Here are my two girls:

6095 and my boy, Alexander, using Augustina as a footrest: 6097

Lights out in 5! Antonia peeking out to say goodnight:

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Contentment means basking on top of a friend:

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[SantaMonica]

I think turtles are in my future.

[amwassil]

Here I am, one week in:

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Looks like the first cable tie at the input end is causing a water diversion. If this continues to be a bare area next weekend, I'll either replace it with a small tie or remove it entirely. After taking the above photos, I toothbrushed the screen on both sides.

[Bacon]

Don't worry about it. It will eventually fill in. Just leave it be, if it's still a problem 2-3 months down the road, then you can modify it. Also be careful not to cinch the zip ties too tight which can cause the slot to pinch closed

[amwassil]

Bacon

Thanks! OK, I'll leave for now and see how it develops. I'm pretty happy there's as much growth over the first week.

[amwassil]

2 weeks in:

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Looks like Bacon was correct, the algae is spreading into the previously empty areas. Again, after making the photos I toothbrushed both sides of the screen. I think I'll let it grow for a couple weeks now without disturbing it.

[amwassil]

3 weeks in:

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I did nothing other than pull the screen for the photos.

I noticed this past week that algae is showing up in the sponge pre-filter and its cover bag. I presume this is minute bits of algae that breaks off from the screen and ends up in the water tank. Is that something normal/usual? Thanks.

[amwassil]

Aug01/15 water test results:

pH: 7.0
NH3/4: 0.0
NO2: ~0.1 - 0.2
NO3: ~80+
PO3/4: 0.0

I suspect a bit of nitrite is showing because I had the filter offline yesterday for several hours for some plumbing maintenance. Very interesting that the phosphate is 0.0. Hopefully, the algae will start eating the nitrates now!

[amwassil]

4 weeks in, two weeks of growth:

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I took a small harvest and will find out later if my turtles will eat it. Then I cleaned the screen thoroughly with a toothbrush. I brushed between the screen and the sides of the slot in the spray bar to make sure that is clear.

Anyone know what's the yellow stuff?

[Bacon]

You should never really "scrub" the screen with a brush, this just sets you back. I don't see anything yellow, or at least, not significant enough to be of concern.

At this point you should scrape and rinse lightly, maybe rub with your palm or fingertips gently, and that's it.

I never scrub a screen with a brush except where it is inserted into the slot.

[amwassil]

Thank you very much. I'll follow you[r] instructions!

[amwassil]

5 weeks (minus a day), six days of growth. I've got a major plumbing project planned for tomorrow, so I checked/cleaned my scrubbers today instead.

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Following Bacon's above advice, I cleaned both sides of the screen with a soft rubber spatula which worked well and left a nice layer of pale green on the screen. I also cleaned the spray bar slot with a toothbrush.

It looks to me like this scrubber is well established. So I'm not going to post any more weekly photos unless someone thinks it's worthwhile doing so. I will post photos if anything unusual appears. I WILL post first-of-month water test results each month. I am very curious how long it will take for nitrates to get down to readable levels on the API test card!

[Bacon]

rubber spatula was a good idea. Screen looks good.

[amwassil]

Water parameters as of Sep01:

1. pH: +7.2
2. Ammonia (NH3): 0.0
3. Nitrite (NO2): ~0.1+
4. Nitrate (NO3): ~40+
5. Phosphate (PO4): 0.0

[amwassil]

I thought I'd mention that both last Saturday and today there was HUGE growth on the screen. It appears to be all green hair algae and hanging off the screen several inches when I took it out of the scrubber box for cleaning. I'm very happy with the amount of growth. Now to see how long it takes to get the nitrates down. As you can see from my water tests on the first, there is still measurable nitrite, which is kind of odd.

[amwassil]

The plumbing project I mentioned 3 weeks ago was to replace the hose, drill out a hole in the bottom shelf of the table and suspend the main pump from the hose coming out of the bottom of the plastic garbage can. My original construction resulted in too much vibration noise; so I thought if I used softer hose and suspended the pump then less vibration would make its way into the wooden table and the garbage can top.

I replaced the original reinforced poly hose with silicone rubber hose. By drilling out the bottom self to lower the pump, I was able to extend the length of hose from the bottom of the garbage can and I think the extra length of soft silicone rubber dissipates the vibration more effectively. Net result is much less noise, so the fix worked. I'm happy.

1. The suspended pump and hose assembly passing through the bottom table shelf:

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2. The airline imputs just above the top shutoff valve:

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3. The airline splitter just below the input into the bottom of the garbage can:

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4. Full view:

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[SantaMonica]

That's about as clean of an install that I've ever seen.

[amwassil]

Saturday, Sep12, one week's growth:

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Here's the algae from both sides:

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After scraping, I rinsed the screen thoroughly and cleaned the slot with a toothbrush.

[amwassil]

Water parameters as of Oct01:

1. pH: +7.2
2. Ammonia (NH3): 0.0
3. Nitrite (NO2): ~0.0
4. Nitrate (NO3): ~40+
5. Phosphate (PO4): 0.0

[perlboy]

What a terrific solution. I have been searching for a solution to removing nitrates from culture tanks of Pacific white shrimp, Litopenaeus vannamei. My plan is to culture PL10 to 3 gram individuals in a nursery, then transfer them to grow-out tanks. For both, I plan to use MBBR (Moving bed bio-reactors), of my own design but very similar to yours, as you do, sized correctly. The pacing problem for me is how to deal with nitrates, since the large biomass will produce massive amounts of nitrates. This is such an elegant solution I can't begin to say how much I appreciate your publishing it. One notion of mine: did you consider using an airlift rather than a submersible pump to provide the water flow for the scrubber? I have ample air (regenerative blowers), am really attracted to airlifts, use them whenever possible and they are essential to MBBRs in any case. Plagiarism is the sincerest form of flattery so I will copy what you have done. Bravo amwassil.

[amwassil]

Thank you for the positive feedback. I'm really glad you think the concept will prove useful to your project! I wanted to keep the algae scrubber out the moving bed so it would not interrupt the overturning water. This necessitated a waterfall type, although I did consider adding the scrubber to the outflow. I am planning to build another upflow scrubber in my main fish tank using a long airstone repurposed from an 'air wall'. I have two smaller upflow drops (Santa Monica 1.2x) in the fish tank now which are working. I'd like to move those two drops to a couple of smaller tanks which would benefit from nitrate removal.

[perlboy]

What you have done is so inspirational I had to look at a variety of different containers. Rubbermaid Brute containers are very desirable: cheap, strong and the gray, white and yellow versions meet USDA Meat & Poultry certification and comply with HACCP guidelines. You may not intend to eat your turtles but my shrimp will be marketed to very fussy consumers. Best about Brutes (you may already know this): The round ones come in 10, 20, 32, 44 & 55 gal sizes and the 32 and larger have domed lids as well as the more familiar flat lids. Unfortunately, the square Brutes only have flat lids. Also, I may build a simple inside stand for the Expression boxes made of 1/2" PVC. Two will fit side-by-side in larger Brutes. Man, I think you dear amwassil have solved my nitrate problem. If you need a source of Brutes, try USP, www.usplastic.com.

[amwassil]

LOL! Correct, no intention to eat turtles. Be sure to start a new thread to document your project. I'm sure all here will be most interested to follow your progress. And, you're welcome!

[amwassil]

Dec01 Water params

1. pH: 7.2
2. Ammonia (NH3): 0.0
3. Nitrite (NO2): 0.0
4. Nitrate (NO3): 40+
5. Phosphate (PO4): 0.0

For some reason the pH dropped to 6.1 before my Nov01 tests. I didn't do anything about that until today. From my recent experience with the two drops in another tank, I added some baking soda to raise the pH, hoping that will stimulate the algae. I'm getting a nice crop of hair algae each week, so maybe it's already eating the nitrates but it was so high to begin with I can't measure the decrease accurately yet.

[amwassil]

I just upgraded the MBBR attached to my 80 gallon fish tank from a 5 gallon bucket to a 10 gallon Brute garbage can. This in preparation to adding a new algae scrubber design to the system. Here's the new moving bed filter:

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In the first photo it is not clear, but the pump is suspended and not touching the wood underneath it. The second photo shows the water return from the filter via 2" ABS pipe. Third photo shows the overturning Helix media and the screen over the outflow pipe end. The media is nicely colonized, as you can ascertain from the brown colour. I will soon turn off the Marineland C360 and let the MBBR take over completely. When I do that, I will monitor water params daily until I'm assured that the MBBR can maintain them.

I've almost completed the new algae scrubber, which I will describe in a separate thread. I haven't finished it yet because I am still deciding how best to put it inline with the MBBR. Most likely I will pump water from the Brute to the scrubber and dump the scrubber directly into the aquarium. I'd prefer to dump the scrubber back into the Brute rather than directly into the aquarium, but I want to incorporate a filter sock to catch algae debris and that would take up a fair amount of space which might interrupt the water movement within MBBR too much. But I haven't made a final decision yet and if I can figure out how to build a compact sock filter unit, I may still end up dumping the scrubber directly to the Brute instead.

[SantaMonica]

That's a good size can. I like large filters.

[amwassil]

I think I have figured out how to attach my new scrubber directly in/out of the MBBR, using a 2" diameter ABS pipe to hold the filter sock under the return. Unfortunately, although I have pretty much finished building the scrubber except for hoses to/from the MBBR, I can't continue until I move my two dwarf gouramis back to their permanent tank. The temporary bowl is sitting in the space I need for the new scrubber and I don't have any other place for the bowl. Hopefully this coming week I'll be able to rearrange things a bit to accommodate the new scrubber.

[Gigaahxl]

I absolutely LOVE seeing great design and engineering put to good use with inexpensive materials. Bravo. The suspended pump is excellent. I assume both the suspension of the pump and its seperation from the system on both inlet and outlet by rubber hose is for noise and vibration. I'm certian that is effective. Can you give me an idea of how effective you feel it is? Love it.

[amwassil]

I absolutely LOVE seeing great design and engineering put to good use with inexpensive materials. Bravo. The suspended pump is excellent. I assume both the suspension of the pump and its seperation from the system on both inlet and outlet by rubber hose is for noise and vibration. I'm certian that is effective. Can you give me an idea of how effective you feel it is? Love it.

Thanks. Yes, the silicone tubing makes everything much quieter and eliminates about 90+% of pump vibration. If you haven't looked at previous posts, in post #24 of this topic, you can see the suspended pump of the bigger MBBR that's attached to my turtle tank. I had originally used reinforced poly tubing. I was not happy with that because it transmitted the vibration pretty much full bore. Noise is a big concern for me because I work all day in the same room with these water pumps. I'm a happy camper now. The sound of falling water is louder than the sound of water and air pumps. :cool:

[amwassil]

Jan01 Water params

1. pH: 7.0
2. Ammonia (NH3): 0.0
3. Nitrite (NO2): 0.0
4. Nitrate (NO3): 40+
5. Phosphate (PO4): 0.0

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[amwassil]

Feb01 Water params

1. pH: 7.0
2. Ammonia (NH3): 0.0
3. Nitrite (NO2): 0.0
4. Nitrate (NO3): 40+
5. Phosphate (PO4): 0.0

Dolomite has proven to be a disappointment. I think the stuff dissolves too slowly for the calcium and carbonate to buffer the pH and keep calcium levels up. So I'm now trying powdered cuttlebone. I just break off a piece and grind it into a powder with my mortar and pestle. The stuff is quite soft and grinds up very easily. I mix the powder in a little aquarium water to get it saturated before adding it slowly to the aquarium in front of the filter outflow pipe. The water gets a bit cloudy but clears up within an hour or two. I'll report at the beginning of next month whether or not it's better than the dolomite.

[amwassil]

Feb07

I added a filter sock to the drain in the scrubber box when I cleaned the scrubber last week. It has cut down on the amount of algal fragments getting into the MBBR and the turtle tank. That reduces the amount of algae that ends up clogging the Hel-x media, which I've been picking out manually each week, and the amount of algal debris in the prefilter in the tank input. So I'm happy with all that. Here's a photo of the sock attached with rubber bands before I cleaned the scrubber yesterday:

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[SantaMonica]

Those turtles don't eat algae?

[amwassil]

Several of my fish species eat it, some enthusiastically. The snails love it. Unfortunately, the turtles don't like it. I think I'll try it with them again, though.

[amwassil]

Monthly update Mar08/16

1. pH: 7.0
2. Ammonia (NH3): 8.0+
3. Nitrite (NO2): 1.0+
4. Nitrate (NO3): 40+
5. Phosphate (PO4): 0.0

Needless to say, this got my attention! I had noticed that the MBBR had a noxious odor for about a month or so, but I didn't realize it was most likely coming from dead/dying bacteria in the media. Fortunately, this happened in the turtle tank so it didn't cause any harm. Turtles live in the water, but don't breathe in the water. Had this occurred in the MBBR attached to the fish tank, I would have lost all the fish in the tank.

I have two suspects about what happened. First, overheating of the MBBR; and, second, insufficient turnover/churning of the Hel-x media. The LEDs in the algae scrubber generate a fair amount of heat. To vent it, I had been propping up the Roughneck lid with a piece of wood. I've increased the venting by drilling several large holes in the lid.

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To get better overturning/churning of the Hel-x, I removed about 1/3 of it and washed the rest. I also changed the water intake flow valve to increase the flow rate. So the media seems to be overturning much better now. The foul odor is gone too. Assuming there is still live bacteria in the media, I expect it will take a couple weeks or so for the water params to fall back to normal again. Hopefully.

BTW, some time ago I managed to break off a flow control air valve in the air intake into the inflowing water tube. This caused a bit of a mess, but fortunately I was able to plug the hole and drain the MBBR without getting too much water on the floor. This experience prompted me to redo the air such that the air lines to into the MBBR over the top of the rim, not into the input water tube. You can see the airlines in the second photo above. No more holes in the tubing for airlines!

[amwassil]

Apr01/16

1. pH: 7.0
2. Ammonia (NH3): 0.5
3. Nitrite (NO2): 2.0
4. Nitrate (NO3): 40.0+
5. Phosphate (PO4): 0.0

This is taking far longer than I expected to start cycling again. It still has a ways to go. There are lots of Hel-x media with little or no apparent bacterial colonization, so my guess is that something killed the bacteria. But I have no idea what. I will probably have to purchase some live bacteria to inoculate the Hel-x again.

The ammonia is down only because I added a reactor loaded with Ammo-Carb. It's about expended and I'm going to replace it with Zeolite. Note that nitrite is up, which I interpret to mean there is some bacteria in the media converting ammonia to nitrite, but none or very little bacteria converting nitrite to nitrate. I am testing pH in this tank daily and keeping it up mostly with powdered dolomite and cuttlebone. If I fail to do so, pH will crash within a couple days down to about 6.0. If pH drops below 6.6 I add a couple of 1/4 teaspoons of baking soda to boost it quickly. All this is for the benefit of the bacteria (whatever there is of it still alive) and the algae scrubber.

[SantaMonica]

What is bringing the pH down?

[amwassil]

What is bringing the pH down?

My guess is a combination of ammonia and nitrate. Ammonia peaked 'off the chart' with my API Ammonia Test kit. At that level and pretty much any/everything above 1ppm I had to bump up the pH daily. Now it's every couple of days. Before the ammonia spiked I still had to bump up the pH every few days or so. The only reasons I can come up with are ammonia and nitrate. I think 'old tank syndrome' is just another name for nitrates.

[amwassil]

Apr03

I bought some Seachem Stability today so I can try to re-inoculate the bacteria. I now wonder whether the lights from the algae scrubber killed the bacteria? Any ideas about that? I am going to add some opaque baffling to prevent light going down into the lower part of the filter container. I can't think of anything else at this point unless some gremlin dumped a bottle of bleach into the tank when my back was turned. :rolleyes:

[SantaMonica]

Light won't affect bacteria directly.

[amwassil]

Apr23

It looks like the cycle has restarted successfully. Ammonia went to 0.0 about 10 days ago and I took the AmmoCarb reactor offline. Ammonia is still 0.0, so I presume the biofiltration is working.

As for why the crash occurred. pH in this tank consistently falls for some reason, maybe because of the bioload imposed by the turtles. I now suspect that pH fell to 6.0 or below and the bacteria in the MBBR either died or just stopped metabolizing. For the past several weeks I have tested pH either daily or every couple of days and added baking soda, ground dolomite and/or ground cuttlebone to keep the pH at 7.0 or above. So far I've added nearly half a bottle of Seachem Stability over the past couple of weeks to recolonize the Hel-x media. With the pH remaining above 7.0 the bacteria appear to be functioning again. Also, algae in the scrubber is growing much more vigorously!

I guess the lesson here is keep pH at 7.0 or above! So I'm doing that in all my other tanks as well, although none of them have the drop in pH of this tank.