Polycarbonate scrubber housing?

[shrtwrec20]

Hi all. I've decided I want to build a scrubber for my tank. I want to put it above my sump and use my inlet pipe from the weir to feed it. The plans are for it to be about 500x300x210. The total volume of my tank and sump is 577 litres (152.5 US gallons). This is the max capacity ie if the tank and sump were full to the brim, which of course they won't be but I decided it best to work the figures to this then if anything it will be slightly over size ;). My screen will be around 19" x 11" (or two smaller screens making the same area, supplies dependent). I may even make the overall length a bit more depending on space.

I am looking to use at least 8 20cfl's but again, dependent on space I will fit more if it's possible.

I want to use 6mm polycarbonate sheet for the construction as I have quite a bit available at no cost to myself so it's the cheap option ;) also it has a higher temperature range than acrylic and is much easier to cut :)

My 1st question (of many to come over the following weeks) is what is the best product to use for sticking poly sheets together in the 1st place?

Also please feel free to give any advice, constructive criticism etc along the way. I like as much info as possible before I begin any project, especially when it's related to my beloved tank.

Thanks
Julian

[SantaMonica]

19" long is almost long enough for 24" T5's... which only put out light for 20"

8 CFL's is 4 on each side. You'll want to hang them sideways from their cords, and use sideways reflectors like the ones that come with utility lights.

[shrtwrec20]

I was thinking something like this. I wasn't going to hang them as such as i want them to stay put, if i need to move it for cleaning purposes etc, so they don't swing around and break anything ;)

http://i49.photobucket.com/albums/f251/shrtwrec20/ATS.jpg

The drawing is pretty much to scale and as you can see i can get 5 each side pretty comfortabley. I will also use a beer can reflector on each bulb. The box will be made from 6mm clear polycarbonate sheet, and I will paint the outside to minimise light loss.

[SantaMonica]

Will there be a bottom?

[shrtwrec20]

Yes mate. If needed i could even fit more lights in the bottom facing upwards.

[DesignsOnline]

Or do what I have done and hand other lights at a different height between the ones you have in place already...
(Ive got 12 cfls runing on mine)

[shrtwrec20]

My main concern at the moment is how i can bond the polycarbonate together sufficiently? And also if this will be enough filtering for my tank? I only feed 1 cube a day if that helps?

Thanks
Julian

[SantaMonica]

Then you need to have the lights near the bottom; not the top. Most filtering will come from the 3D at the bottom of the box as it starts building up. Light underneath won't do any good; they'll covered by growth quickly.

[Floyd R Turbo]

You need to read up quite a bit and learn how to properly fabricate a box, especially if it is going to have a bottom, as you have to build it as if it were an aquarium. Forget polycarbonate. There isn't a tank builder in the world that would build a watertight box out of polycarbonate. ONLY acrylic. Bond strength is not high enough.

[shrtwrec20]

Ok thanks for the info guys. Can get my hands on a sheet of 6mm acrylic which is 1m x 2m so that should be sufficient. I'm in the process of building a 3D diagram/plan so will post that up when it's complete and you can give me some pointers on that ;)

Thanks
Julian

[Floyd R Turbo]

yes that will do. The next thing you need to figure out is if you can get Weld-on 4 where you are at. Outside of the USA it can be hit or miss, but #3 or #4 is what you want at a minimum, or something chemically very similar.

[shrtwrec20]

I found this uk supplier of acrylic adhesives. I couldnt find a weld on supplier other than the PVC pipe cement. Any idea if any of these products will work?

http://www.hindleys.com/catalog/index.p ... h=7_57_516 (http://www.hindleys.com/catalog/index.php?cPath=7_57_516)

Thanks
Julian

[Floyd R Turbo]

Yes the liquid solvent cement is your stuff. dichloromethane is also called Methylene Dichloride and it the active ingredient. Here in the states you can buy that straight up. Works fast though. It looks like there is another ingredient in that stuff, but not familiar with it. Should be fine. I think I've seen it referenced on the DIY section of RC's big acrylics fabrication thread, which is worth the read if you have a week. It's 8 years old and I think 5000 posts but tons and tons of good info.

[shrtwrec20]

excellent. I'll check that out when i get some free time/weeks lol. Thanks for the help.
Here is the basis for the design. Pretty straight forward, will just need to incorporate some latches to hold it together and make it easy to dismantle for cleaning and bulb replacements

http://i49.photobucket.com/albums/f251/shrtwrec20/ats2.jpg

http://i49.photobucket.com/albums/f251/shrtwrec20/ats1.jpg

Thanks
Julian

[Floyd R Turbo]

You need a cross-brace across the top edge of the box or else it will bow outwards. A 1" wide strip perpendicular to the side window within an inch or two of the top will do.

[SantaMonica]

And reflector material on the walls.

[shrtwrec20]

You need a cross-brace across the top edge of the box or else it will bow outwards. A 1" wide strip perpendicular to the side window within an inch or two of the top will do.

I'm not exactly sure where you mean?


And reflector material on the walls.

I have a couple pieces of mirror finish acrylic sheet which i'm going to try and encorperate. If not it will be good old beer cans ;) I have plenty of them :lol:

[Floyd R Turbo]

The SM100 has a piece of horizontal acrylic mounted perpendicular to the top edge of the screen box. This is not only to protect the light fixture from water dripping on it when you take out the screen, it also provides a brace along the top edge of the box. Acrylic will bow outward in your design. You need to build it like and "I" beam (or "H" beam on it's side).

[shrtwrec20]

Right, I think I get it.
I have added here a 20mm square bar across the length drilled with 10mm holes. This should strengthen the box and also gives a way to attatch the light holders to it, buy fitting them with dowel pins to suite the holes in the bar :D

http://i49.photobucket.com/albums/f251/shrtwrec20/ats3.jpg

[shrtwrec20]

Right. My LFS can supply ambroid pro-weld, which includes methylene chloride, and is used for acrylic tank repairs. So I'm going to order up some of that and my pipework, unions, elbows etc and will hopefully be able to pick it all up Friday and make a start :D.

On another note. I've seen the design for your scrubber (floyd) and I love the way it opens up to make screen removal easy. I might try to do something like that as it would save me having to remove the box every week. Excellent idea ;)

[Floyd R Turbo]

The 2 improvements I would have made on my design are 1) adding the crossbrace along the top of the box, and 2) better light blocking. Also bottom drains are quite gurgly and noisy, still trying to figure out how to improve on that.

[shrtwrec20]

Maybe If you put a breather hole above the water level in the box? Would help with air/water displacement and stop the gurgling?

[Floyd R Turbo]

It's an open top box.