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Acrylic Thickness

Discussion in 'General Discussion' started by LED T, Jan 7, 2018.

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  1. LED T

    LED T New Member

    I am currently building an algae scrubber made from .220" acrylic. I'm also making a wooden stand for it to support the base held down by nylon screws. The dimensions of the scrubber will be L=18"x H=14"x W=8"(base). It will have a 4" wide growing chamber? in the middle of the base.

    The screen is a roughed up knitting pattern 14"x 10".

    The scrubber will have a dedicated 550GPH pump with a ball valve.

    I'm using weld on 4 for the acrylic adhesive. I haven't glued any thing together, but have cut all the pieces to size. I am waiting on bulkheads to drill what holes i need to before glueing. This is a dumb question now, but What would be the minimum thickness of acrylic required to hold the water under pressure? I am only about $30 into this project. If i need to start over I'm not too worried about it.
  2. Turbo

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


    Considering that the box will likely never really be full of water, and that it's relatively small, the standard aquarium calculator doesn't really apply. 0.220" is fine for the height you are building.

    But the first question I have is, how much are you feeding? 14x10 is a huge screen, that's big enough for 11 cubes/day if you light it properly, is this for a very large tank?
  3. LED T

    LED T New Member

    Sorry in advance for the long post. It's a 125G reef tank with a 40B sump. My tank is built into the wall of my finished basement. I have a fish room behind the tank that's 7'x11' for filtration, fragging, and tinkering around. It's more of an area specifically for my tank. It doesn't have a door.

    I have 11 fish that are fed about 2 cubes a day. Plus i have a small Fuzzy dwarf lion fish that i cut up silversides for. I also feed one cube of blender mush every other day. i keep the plastic cube trays for my special blend stuff/blender mush. The fish have a pretty big appetite i spot feed or hand feed all my fish.

    I also feed a 1"x2" square of nori for my herbivores every 2 days. I don't run a carbon or GFO reactor but use the Carbon and GFO filter floss that i place in my bubble trap before my return pump.

    My fuge was completely cleaned out and i placed live rock in its place. I am having a 60G custom built sump made for me 43"x18"x18". I should have it in one or two weeks. I would like to have the algae scrubber going by then. That's the whole reason for this. I will have a very large area in the sump for a fuge. It's can hold 15-20g of water depending on where i place the adjustable height baffles. If i don't need the fuge i will use it as a frag tank. I have a 108W led 36x3W full spectrum that i plan on using for it. It's completely adjustable and on a timer. The purpose of the fuge is to grow colorful macros and maybe house some cool inverts. Create an area for pods to grow out in. Not so much nutrient export, but if it helps then I'm not going to be upset.

    I would honestly like to get away from my skimmer. Or use it on he lowest setting. Ever since i added a larger skimmer it brings in extra CO2 from the basement. And drops my PH. I dose what kalk, and all supliments i can to bring it up, but my Alk is already around 10dkh. I don't want to go much higher than that. I am currently using a CO2 scrubber which works well, but the media alone for the CO2 scrubber is $50 every 2 months. My PH before the CO2 scrubber was 7.6 and with the scrubber it's 8.1. I would like the ATS to help with my PH and keep it stable. I would like to get rid of the CO2 scrubber, because of the cost. If i could get into the 8.2 or higher range with the ATS i would be very pleased.

    So now that you know my system, and my issues i would like this algae scrubber to fix. What sized screen do i need? How much flow do i need? and about how many watts of leds do you think it needs to have on both sides? I have about 200 extra 3W LEDs that I can play around with. And it doesn't take long for me to build a timing circuit for it.

    Your way of building scrubbers is a little different than I have researched elsewhere. I read the screen had to be 1 square inch for every gallon of water volume. Your method is based on how much you feed. Which makes sense. And it's a WHOLE lot easier to do it this way.

    What do you recommend i start reading? Or do you have any helpful links for me? I am very interested in Algae scrubbers. So, any help would be appreciated.
  4. Turbo

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

    I started up a freebie Zoho page a while back to keep everything in one place and up to date...well, at least, sort of up to date

    Algae Scrubber Basics - Overview

    The only thing that has significantly changed since I wrote the "basics" writeup (posted here, on Reef2Reef, ReefCentral, and various other places) is the LED lighting, as that was a relatively new thing back in 2012 when I put out the 2nd version of the Basics. But, I have included that update on the Zoho page.

    The information you are reading regarding 1 sq in / gallon is quite outdated, that got shifted to the feeding-based guideline of 12 sq in / cube / day sometime in 2011 I believe. It has stood the test of time, and you can apply de-rating for instances where you are maybe not using the ideal lighting or flow.

    So if you start here:
    Algae Scrubber Basics - Planning Your Algae Scrubber
    Then figure from this
    2 cubes/day
    This is a bit of a tough one to estimate, call it 1-2 cubes
    0.5 cubes/day
    1/4 cube every other day

    I would say you're near 4 cubes/day.

    Then look here:

    Factor in this
    The skimmer is already doing some of the work, so is the fuge, so even if you estimate on the high side for feeding, these take up some of the load so you're back to 4 cubes/day or thereabouts

    Next you would figure up what screen dims fit your planned lighting. With DIY LEDs you can make this however you want. 7x7 = 49 sq in makes it easy but 6x8 might be fine too. I also recommend that if you oversize, don't go much over 2x what you feed. So that gets pretty big in this case, 100 sq in would be double size.

    For a 7" wide screen you would shoot for ~30 GPH/in (25-35 is a good range of flow the guideline is 35 but in reality I've seen great growth with lower flow) so 7x30=210 GPH, 7x35=225, etc. Could go as high as 300 GPH but not until you have a good base of growth, and then only if you need it (like you want to push the limits of the scrubber, you have available nutrients to support that, etc)

    Then look here Algae Scrubber Basics - Lighting: LED for the LED formula, which was updated a few years ago and still stands

    That'll keep you busy for a bit!
  5. LED T

    LED T New Member

    Cool thanks Turbo! I'll have some questions for sure when i finish reading all of this.
  6. LED T

    LED T New Member

    Great information.

    I would like to add You don't cover the importance of cooling the leds and how temperature can effect the lifespan.

    These are my three most important rules when it comes to any type of DIY aquarium light.

    1. Power them correctly.
    2. Keep them cool.
    3. Keep them dry.

    Those are the three things that will shorten the led lifespan if not done correctly.

    And the spray on moisture protection is called conformal coat.

    I use Konform by Chemtronics.
  7. Turbo

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

    Konform SR? Just been googling that, that's $$ stuff!!

    Absolutely, I stayed away from this aspect of the discussion because I wanted to focus mainly on the spectrum and layout. I figure that if someone is going to DIY an LED fixture, they are either going to 1) go the uber cheap route (like buying off eBay and mounting to a 4x4 electrical box, literally have seen this) or 2) dive into LED fixture building and buy quality LEDs and take the time to actually understand what heat sink they need and how to protect the fixture or 3) buy something off-the-shelf.

    But I suppose that it wouldn't hurt to at least mention it! I'll add that bit of information the next time I update it. I need to update pics anyways
  8. LED T

    LED T New Member

    You are right. You also don't want to give people too much information, because people are going to do what they want to anyways.

    I made a make shift algae scrubber to get my screen started. I want to get a jump on it while i am building my scrubber. I think i am going to design one and have my friend make me one that owns his own acrylic shop. He is the one building my custom sump. I told him what i was doing and he was very interested in incorporating it into my sump. He said we could even make it the same colors as the sump too. He can design panels on his laser and cut them out perfectly, and glue them so i don't have to worry about it. And since i build lighting for him as well. I am going to get this for free or at a deeply discounted price.

    I decided with a 10"x8" screen. I will leave a little extra room on the sides and bottom to increase the size if i plumb in another tank into this sump. I'll only have to remake the screen and pipe.

    My friend gave me two of his 165W black box leds to have. Since i have done a lot for him he upgraded his lighting. And decided to give them to me. I personally don't like the black boxes. But i wouldn't be against running one over my refugium. That size light would outcompete my tank lights at night for sure. And i wouldn't have to build a mounting bracket for it.
  9. Turbo

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

    I've seen people use more "full spectrum" lamps/fixtures and that can work, IMO the growth-spectrum works best, and Warm White second best. If those were DT lights, they likely have a lot of blue in them, and for some reason that doesn't seem to work for everyone. But I've seen it done, Karimwassef of ReefCentral has a mega huge scrubber using them on one side (literally it's 4' tall and 2' wide I think)

    As for the laser cutting, that's probably fine for a scrubber enclosure but just a tidbit of info on acrylic fabrication, when you weld laser cut edges, they will tend to craze. The same thing happens when you flame-polish acrylic and touch it with any kind of cleaner (or denatured alcohol). Crazing is an indication of embedded stress in the acrylic and mostly aesthetic so it's not like the box is going to suddenly fly apart. But just so you know, if that happens immediately or over time, that's why. The remedy would be to laser cut to a slightly larger dimension (like add 1/16" to each) and then pass each edge through a router or jointer to take 1/32" off before welding.
  10. LED T

    LED T New Member

    My friend has been doing this for years. He specializes in custom aquariums, sumps, and much much more. His products don't craze. Since I'm not making it... this input wasn't really necessary.
    It would be silly IMO to use this on a scrubber for my application don't you think? That's why i said i was going to use it over a refugium. I'm not entering into an algae growing competition. So, for this purpose it should be fine.
  11. Turbo

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

    I missed or misundeestood where you were using them.

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