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Discussion in 'Algae Scrubber DIY' started by Dave Snider, Feb 25, 2016.

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  1. Dave Snider

    Dave Snider New Member

    We sure love acronyms in our hobby don't we :).

    I build a do-it-yourself (DIY) polyvinyl chloride (PVC) algal turf scrubber (ATS) with light emitting diodes (LED) that I bought from Amazon. I'll try and describe it for you here with lots of pics to follow. I'm really thankful for all the people on this site, so this is my way of trying to contribute to the community.

    DIY: First and foremost, if I could afford it, I WOULD BUY one of Turbo's new units. There is

    nothing better than a turnkey system that is tried and true. But there were >100 people ahead of me on the waiting list, and I have a wee algae problem in my tank that I'd like to conquer. Plus I really enjoy building things, so I opted for a DIY for my first ATS. For the record, I mean if I could afford to wait - I would've shelled out the $$ to buy Turbo's Rev 4.

    PVC: Huh? This is strange... As I was wandering around Home Depot looking for sheets of
    acrylic to build the ATS, I found something called PVC Trimboard and I got an idea. I bet I could build this thing from PVC 'lumber'! I have a bit of experience with woodworking and figured it would be worth a shot. (Here's a link to the product)

    The product is designed for use as window trim or house siding, and because it is 100% PVC it won't rot. It is not very dense and it is easy to work/cut. Apparently, there is another (similar but more dense) product that is designed for building patios/decks or for structural outdoor furniture.

    But PVC lumber in the aquarium? Hmmmm.... I haven't seen any other DIY equipment made from this product so I was a little nervous at first. But it is 100% PVC, so really, it ought to be just fine. If my tank crashes I'll definitely turn this into a 'For the love of God, don't use PVC lumber for anything ever in your reef tank' thread! :)
    LED: I am not electrically-inclined and I wanted to buy a LED light that would suit my
    needs. So after reading another post in this forum I decided to purchase these lights from Amazon and try 'em out. So far I'm happy I spent the money on 2 of these 20W lights. They appear to fit the current recommendations in terms of wattage and spectrum 16 reds (660 nm) & 4 blues (445-450 nm). I am running them on a timer from 6pm to 10 am (16 hours total), but this may change depending on future growth/needs.
    TANK: I have a 90 Gallon mixed reef tank that has been running for >1 year (cycled &
    inhabited with livestock for 12 months). I used dry Pukani rock and attempted to bleach out ('cook') as much dead organic matter as possible before I set the tank up. But I think it is still slowly leaching phosphorus. I have had the typical new tank blooms of diatoms, hair algae, etc... All in all, things have gone pretty well for me so far. I have been running GFO for a few months now, but the hair algae is still a nuisance. I have a low bio-load and do not overfeed. Along with my coral, I have 2 clowns, a coral beauty, a mandarin dragonet and inverts.
    DESIGN: Well, like any good DIY'er, I did my research and tried my best to learn from
    everyone else's experience. There is an awesome wealth of info in this site, and I made good use of the threads in the 'Resources' section. Some of them I read and re-read a few times :).

    I have a Herbie Drain set-up and a sump in my basement with all the ugly/noisy equipment. I measured the flow coming through my main drain (equipped with a true gate valve to tune the siphon) and I got about 245 gph of flow. My return pump has a decent amount of head pressure to overcome (~8 feet?) so that is the flow I'm left with. I plan to increase my fish load over time. Maybe I'll get to a 2 cubes/day feeding load? Admittedly, I still find this metric hard to decipher but we need some way of quantifying the nutrient load...
    So I determined that I wanted a 6" by 6" screen, lit on both sides. I figured the 2 x 20W LED's would do the trick. If they are too powerful then I hope to compensate by reducing the photoperiod.

    I had to design an ATS box that could hold water. After putting together a design on paper, I set out with my 70's-era table saw had a lot of fun shredding plastic wood. I cut dado joints to join the bottom and sides. I made sure the cuts were relatively smooth, and if needed used a file and/or sand paper to quickly smooth out the cuts. I used PVC primer and cement on all the joints.

    Because I bought 1" by 10" by 8' boards, the 'lumber' was actually 3/4" thick by 9 1/4" wide. This was wide enough to make the bottom, top, and the two narrow sides. But the wider sides that housed the window for the lights needed to be bigger. So I joined two pieces together using a double rabbit joint (lap joint).

    Does it hold water? Yes! Any leaks? No! Alright!

    I cut a rectangular hole slightly bigger than the size of my lights (lights are 180 mm x 140 mm). I bought a thin sheet of Lexan (polycarbonate) and cut out two windows on the table saw. They overlap the cutout by ~1" so there is plenty of surface area to seal the window to the sides. I used GE Silicon I for this and it has held up very well so far. I let the silicone cure for 48 hours. Note: in normal usage this seal will never be submerged.

    I used 3/4" PVC for all my piping. I cut the slot using my table saw. I set the pipe in position with my fence and slowly raised the blade up into the pipe, then moved the pipe along the fence into the blade. I cleaned up the cut and slightly widened it using my Dremel tool. The final slot length is a fraction over 6" and a hair over 1/8th of an inch wide. I found a great PVC union at Lowes that I really like. It is about 5" long and I find it easy to open/close. Easier than the other ones. Plus it has a gasket that fits over the pipe (see pictures), which provides a solid seal better than an o-ring that can wear out over time or get crushed by improper connection.

    I attached the screen using zip ties (loose not really tight). I bought plastic grommets that snap in place at my local hardware store. I also made a simple 'drip stop' using leftover tubing from my skimmer and zip ties. Not my idea - something I read on a forum somewhere. Easy and effective.

    I used a 1 1/4" keyhole saw bit to drill out a hole for the drain pipe connections. I had to slightly widen this using a sanding tool on my Dremel to make a really snug fit for the 3/4" PVC pipe. I made two hole, one for a main drain (equipped with a cheap ball valve) and one for an emergency drain that comes out the side ~2" from the bottom. Doing this allows for an imperfect Herbie Drain setup on the cheap. I didn't want to spend the $ on an expensive gate valve. I was able to tune the siphon with the ball valve.

    One trick: I used a bunch of the 'saw dust' plastic shavings to plug up gaps that I felt were a little too large for me. When I was gluing up joints (the drain pipes specifically) I mixed some shavings with the PVC cement and packed it into the joints to build up the connection a bit. I just used my fingers. It seems to have worked well.

    Another line of defense: I sealed all seams on the outside of the ATS with silicone. Just to be safe. If any of the PVC joints didn't take 100% (which didn't happen), then maybe the silicone would help me out... Plus I sized the ATS to sit inside of my sump in case of a catastrophic leak.

    I made a false bottomed floor (yes I borrowed the idea from Turbo). After some searching I read the purpose of this is to reduce the likelihood that algae clogs up the drain pipe. I made wee little legs for the false bottom with 1/2" PVC pipe and drilled holes so I could stick them in place. Once I got the ATS running I found it was pretty loud. So I cut up a small piece of blue foam and placed it in there to help soften the splash of water (not sure it helps much). Either way, it isn't so load that I hear it when I leave the area of the sump.

    I used the normal canvas screen that is recommended. I left a smooth strip (1 1/2" wide) near the slot to discourage algae growth. I roughed it up with a hole saw, then mixed up some concrete I had laying around. I picked out the large stones, then smeared it all over the screen and left it covered in wax paper for about 2 days. I took it out and washed it off and a light coating of calcareous mortar did remain. This may help get the hair algae established. See initial growth in pics below.
    I haven't incorporated a light blocker yet. I may need to in the future - time will tell.

    Finally, I made a stand for the ATS out of scrap pieces. It allows the ATS to sit on top of the stand, centered inside my sump in the middle compartment.

    Well I have had it online now for 9 days. The first day I was worried because the flow seem to be preferentially directed towards the one side of the screen. This seems to have corrected itself now and flow is pretty even across the width of the screen. There is a good 'sheet' of water flowing down the screen. Growth of green algae is starting :) I'll keep updating this thread every now and then to report success/failures. I think people may be interested in how well these lights perform...


    Attached Files:

  2. Dave Snider

    Dave Snider New Member

    A couple more pics.

    Attached Files:

  3. Dave Snider

    Dave Snider New Member

    And a few pics of my young tank (showing off some of my soon-to-die algae) :)

    Attached Files:

  4. Dave Snider

    Dave Snider New Member

    Forgot to mention that I'm open to all suggestions for improvement/questions. For starters, I wonder if I should reduce the photoperiod? I notice a little less growth in the center of the screen where the light is most direct. Perhaps photosaturation? Right now lights are on for 16 hours.
  5. MorganAtlanta

    MorganAtlanta New Member

    You might want to put a circle of light diffuser in the center of your light. That will cut down the intensity in the middle where your light may be too powerful while keeping up enough intensity at the sides.
  6. MorganAtlanta

    MorganAtlanta New Member

    Cool idea with the PVC board. Seems like it would make it simpler to knock something together with. Every scrubber idea I come up with costs me $150 in acrylic.
  7. Dave Snider

    Dave Snider New Member

    20160229_211520.jpg Thanks for the suggestion. Think plastic food film/wrap, folded up into a square, would work as a decent light diffuser? I'm giving it a shot now. The lights don't get hot (hardly warm even). Nowhere near as hot as a microwave. I'll take it off if/when I get better growth in the middle.
  8. MorganAtlanta

    MorganAtlanta New Member

    Maybe. I was thinking of those panels used on fluorescent fixtures, but you probably only need a 2x2 inch square instead of a 2x2 foot square. Probably anything that will block/diffuse 30% of the light would help.
  9. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Those multichip fixtures get very hot. I would not trust saran wrap to hold up in that situation. You would be better to use some kind of hard acrylic diffuser like the kind they use in ceiling-mounted light fixtures (recessed "troffers"), which you can find in 2'x2' or 2'x4' sheets in the ceiling tile section of hardware stores for a few bucks
  10. Dave Snider

    Dave Snider New Member

    Thank you both for your input! This fixture doesn't really get very hot. After several hours on time, I am able to place my entire palm directly on the glass in front of the LED chip and leave it there. However, the acrylic diffuser would likely work better so I'll try and pick up a tile of it this weekend.
  11. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Sounds good, thanks for the feedback on the fixture heat. Each fixture is different, sounds like yours is OK with the saran but that probably is still not an idea solution. Look for Plaskolite diffuser at Lowe's
  12. Dave Snider

    Dave Snider New Member

    I picked up a diffuser panel last weekend and cut it to shape. After reading a little more carefully I see you suggested to make a smaller diffuser than I've made (mine covers the entire light). So maybe I'll trim it down.

    I did reduce the photoperiod to 12 hours (from 16). I'll leave it another week to see if the growth fills in, but maybe I should reduce the lighting time a little more.

    These pictures show growth after 3.5 weeks of the ATS going on-line. Would this be considered a 'good start'? Open to suggestions.
    13March2016_1.jpg 13March2016_2.jpg
  13. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    have you considered using a rotatable ring instead of the zip ties? Just get a coupler for that size pipe and cut off a ring about 1/4" thick with a hacksaw, ckip about 1/4 of it out with a wire cutters, and round the corners with sandpaper. Then just snap over the pipe. Cut one of the tees out of the screen to line up with the ring and you're done. A lost easier than replacing zip ties every cleaning and it's kind of self-adjusting, meaning, the screen tends to center itself in the slot.
  14. b4tn

    b4tn New Member

    I am very interested in this PVC board stuff. The only thing holding me back from building an enclosed scrubber is the Acrylic. First I have zero experience working with it. And second I can seem to find it for less than $150, and that not even guaranteed the cuts will all be the exact same size. PVC board I could easily work with. The only stuff I found worries me because it seems to be treated with some sort of fire retardant and it is listed as mold and mildew free. I would hate to put some sort of treated plastic in my reef.

    Veranda 1/2 in. x 12 in. x 8 ft. Reversible Cellular PVC Fascia-H120WWS2 - The Home Depot
  15. Dave Snider

    Dave Snider New Member

    The product I used is made by the same manufacturer. How did you determine that it is treated with a fire retardant? I would bet it is listed as mold and mildew free not because it is treated with a fungicide, but because it is made of pvc (not wood, which is susceptible to rot). This is plastic - pvc is a kind of plastic that can take various forms. We use it in flexible tubing with barbed fittings (vinyl tubing), or semi-rigid piping (spa tubing), or rigid pipe (sch 40 or 80 pvc). I would do as I did and phone the manufacturer to ask questions.

    My ATS has been running for 4 weeks now and I have not lost any fish or seen any noticeable harm to coral or invertebrates. Actually my coral are looking better and better. Good colour and growing strong. I understand your hesitation - I was hesitant at first. But so far so good.
  16. Dave Snider

    Dave Snider New Member

    Thanks for the suggestion. I've seen that cool idea on other posts. I may need to do that down the road, but for now the screen is loosely set into the slot and I can easily rotate the screen out of the way to clean the slot. And because the union connection is so easy to remove I can take it apart from there each time to clean the screen. I have a ball valve upstream to completely shut off the flow. Because I have a Herbie Drain setup on my tank all the flow goes down my emergency drain (temporarily) when I shut off the flow to clean the screen.

    I haven't yet cleaned it because I'm letting it get established. Looking at post #12 above, do you think growth is coming along ok? Or is it slow to establish? Wondering if I should do anything different or leave it be?
  17. Kentth

    Kentth New Member

    I have found Acrylic very easy to work with. Find a locally owned window and glass shop, they will have a box full of scraps. We have three in my town and all are more then willing to make you a deal on their scraps. Sometimes they don't even charge me for them. I use Weldon 4 to bond everything together. Reefcentral has some very good threads on how-to build with Acrylic.
  18. Turbo

    Turbo Does not really look like Johnny Carson Staff Member Site Owner Multiple Units! Customer

    Yes it looks pretty good. I might give that a light cleaning to get the slime off, just a swipe of the palm on each side and a quick rinse in tap water, but that's all
  19. Dave Snider

    Dave Snider New Member

    Okay - thanks! I'll stop worrying and let nature take it's course! Here's a pic from today. I'll stop posting in this thread now and create a new one under the new sub-forum that was just made to assess the effectiveness of after-market lights.
    2016-03-18 13.33.26.jpg 2016-03-18 13.34.05.jpg
  20. Xtc_link

    Xtc_link New Member

    Awesome growth, thanks for the thread and pics! I myself have left pvc sheets submerged for months with no issues. I think there is some raising my skimmer up.

    Debating on using it on my barebottom but it's a 150 and there's a lot of rock to lift out first, lol.

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