anyone ever use a cpr backpack pre-skimmer box?

[matt]

hey, I have a totally different use in mind for this than it was intended for. however, it will only work if the box is, or can be made to be, watertight.  That is, it would be a an overflow comparment that does not leak back into the tank if raised above the water line.  I can't tell from pics if it is open bottom or has drilled holes on the side for screws.THANKS!

 

http://www.aquacave.com/Bak-Pak-Pre-Skimmer-by-CPR-Aquatics-P1362.aspx

 

[Origami]

I had it once. The bottom is closed. There was a tapped hole in the side where a thumbscrew went in and held the box in place by clamping the box against a powerhead that pushed water and air into the skimmer body. I don't recall the other holes on the sides of the box, but they're probably there to give flexibility on setting the height of the box (in which case they're probably tapped). You would have to plug these if you didn't want water to leak back into the tank.

[matt]

Tom, thanks. Do you remember what material it was made out of? That is, what material would be best if I wanted to bond a plate over those tapped holes? 

 

I'm obviously still exploring the gravity ato methods in another thread, but this might be an option to create an internal display tank compartment where I'd isolate my low water level...maybe put a small pump and maybe even a heater if it worked out. Isolating the low water level in something this size means I could grab an avast ato inside it. You think the avast ato mount would hold through a 5.5g glass wall and the wall of this overflow box?

[Origami]

looked like plain old black acrylic.

[Integral9]

I have a CPR Aquafuge + PS.  The overflow box is made from black acryllic and there are 3 holes in the overflow box's side, all tapped.  THe rest of the box is sealed.

[matt]

Thanks, guys! This might solve my conundrum, if not my gravity ato curiosity.

 

If its an acrylic box then I should just be able to find some scrap acrylic and then I could weld on a small plate over those holes. I'd also likely trim down the top so less (or no) corner overflow is in use. A little pump thrown in and I bet I can make this a low water level area.

 

Integral - would you mind checking the PS box measurements...including acrylic thickness?

[Origami]

Thanks, guys! This might solve my conundrum, if not my gravity ato curiosity.

 

If its an acrylic box then I should just be able to find some scrap acrylic and then I could weld on a small plate over those holes. I'd also likely trim down the top so less (or no) corner overflow is in use. A little pump thrown in and I bet I can make this a low water level area.

 

Integral - would you mind checking the PS box measurements...including acrylic thickness?

If you want it pretty, take shavings of the black acrylic that you cut off; melt it in acetone, MEK, or methylene chloride; and then use the resulting putty as an acrylic filler. Sand and polish it with an acrylic scratch removing kit, and it'll look nice all around. Of course, if one side is up against the glass, you can just turn the repaired side to the back so nobody sees it.   LOL.

[matt]

If you want it pretty, take shavings of the black acrylic that you cut off; melt it in acetone, MEK, or methylene chloride; and then use the resulting putty as an acrylic filler. Sand and polish it with an acrylic scratch removing kit, and it'll look nice all around. Of course, if one side is up against the glass, you can just turn the repaired side to the back so nobody sees it.   LOL.

 

Interesting, I've not really done any work with acrylic so I will keep this in mind. My current thinking was that I'd weld a plate over the holes from inside the box...can't take up too much space and then I'm not fussing with the outer surface and scratching it up etc.  However, what is the best acrylic weld for this kind of work?

 

I still need to know how thick the acrylic is so I can figure out if an avast ato mount will hold through the glass wall and acrylic wall. However, reefgeek helped me out with total outside dimensions on these units....I just don't know:

- exact insided dimensions

- the height at which the overflow corner starts to let in water

- and the various compartment sizes should I attempt to use the combined combination box with PS+bubble trap.

 

Bubble Trap (would require welding on a bottom) - 4.8" x 2.0" x 7.0" (L x W x H)

Pre-Skimmer (welding on plates to cover holes) - 4.5" x 2.0" x 7.5" (L x W x H)

Combination box - 9.3" x 2.0" x 7.5" (L x W x H)

 

See: http://www.reefgeek.com/filtration/protein-skimmers/cpr-aquatic-protein-skimmers.html

 

Note, my 5.5g is approximately 16" x 8" x 10"

[Origami]

Honestly, I can't remember how thick the acrylic was on the box because it was years ago when I had it (or one similar). Since it's not under a lot of pressure, you may even be able to just fill the holes with either (1) an appropriately sized nylon screw with some thread compound on it or (2) aquarium sealant mushroomed at either end. If you choose to weld bit of acrylic on the inside, you can use either Weldon 4 or Weldon 16 (or the equivalent). Weldon 16 would be easier to work with. You could also just "glue" the acrylic plate down with some aquarium sealant and that would probably work just fine.

 

It sounds like Integral9 may still have the box at home, so perhaps he'll weigh in with the thickness of the acrylic.

[Integral9]

Sorry, just saw this today.  I'll take a look when I get home.  It's probably around 1/8", it's pretty thin.

 

A nylon screw would be ok to fill the holes.  The problem w/ the holes is the threads give out too easily.  And I don't see a need to get fancy w/ the building materials.  I'd use a hot glue gun and tape some wax paper to the inside to keep the glue from spilling into the box before it cools.  Remove the tape and wax paper when done.  

 

As for making it a low water level area, the trick is securing it in place.  As the water level in the box goes down, the buoyancy increases, increasing the upward pressure on whatever you use to hold it down.  Also, the water crashing into the box tends to make the center of buoyancy / gravity (which ever) change so you will need to either have a very secure spot or secure it in 2 locations.  fwiw:  After the threads wore out, I used to use a wooden shim between the pump and the box to hold it in place.  It worked about 90% of the time. 

[matt]

Integral - many thx! ...and please let me know

 

I'm thinking I would put it under the lip of the trim in a corner, so two sides would have resistance from upward buoyancy pressure (even if I end up using spacers that allow drainage to occur below the trim).

 

so it does appear to be just basic acrylic? the hot glue sounds like a really simple fix, but it would be nice to know an acrylic weld made a leak impossible. i'll have to think about that a bit.

 

hoping the thickness is like you remember. I need to double check my tank glass thickness too, but I should be good given it's just a 5.5g. The avast mount supports 5/8" thick glass ...so it sounds like I'd have a good amount of strength in the avast mount.