Beware of the 24" ECO-TYPE REFUGIUM WET DRY SUMP on EBA

[Tim Marvin]

Hmmmm, about 20 gallons?

[manny]

Isn't it closer to 15 gallons?

[Tim Marvin]

Probably, I am just kinda picturing it in my head. Unfortunatley the product was not misrepresented, but we could use it as a teaching tool if anyone wants to buy it we can put it together at the meeting. The other option could be, if willing, raffle it off and the money collected can go to Kaiser up to $55 and any overage can go to the club. We could then put it together for the winner.

[matt]

Hey Kaiser;

If you end up keeping this sump kit and want some help putting it together, let me know. I'm real busy for the next couple of weeks, but I could probably spend a little time at least getting you started. Or, at least I could have a look at it and give you some very clear instructions, and inspect the parts to make sure they'll fit properly. If you had a leaky sump before and tried unsuccessfully to fix it with weldon #16, don't feel bad. That stuff is almost useless for that type of repair. For that you need weldon #40. I wouldn't give up on it if you like the final product; I'm sure I can get you straightened out on it. The only thing is, it's extruded acrylic, I can see the blue F on one of the pieces. That's Cyro FF, their extruded brand. You could use those pieces as templates for a nice cast acrylic refugium if you really like the design. (Then send it back; using the pieces as templates does not damage them in any way) Here's a hint; try taping the pieces together, at least the four outer walls, then set it on the bottom. If there's no overhang, i.e. if the bottom is not oversize, then you might have trouble getting a perfect joint between sides and bottom. The right way to do it is to cut the bottom oversize, set the sides/ends arrangement on it, glue, and flush trim off the excess on the bottom.

Richard makes a good point about the design. On my sump, the baffles are at the beginning of the flow, leading to a large area that the return bulkhead draws from. This is the part of the sump that the level will drop in due to evaporation. Also, remember that there is a direct inverse relationship between volume and water flow-through speed in different compartments of the sump. I like to get the water flowing fast through a few baffes, then end up in a nice big compartment where the flow is much slower before going to the return. I find this really cuts out the micro bubbles; they have time to float to the surface in the slower water. In the photo of the finsihed product, it looks like the sponge is there mostly to trap bubbles. Unfortunately, if you're going to use this as a refugium, it will also trap pods and any micro-life you wish to feed to the tank. Kind of defeats much of the purpose of a refugium.

PM me if you want some help. I'd tend to avoid a glass sump; a nicely built cast acrylic sump will last forever and you can machine for bulkheads, skimmer in-out, etc, easily.

Matt

[Tim Marvin]

What are the big draw backs with extruded? How long should this sump last if glued properly?

[TexasState]

Is the two bulkheads included? I'll buy it from Kaiser if Matt can use it as a teaching tool and put it together at the meeting. How long do you need to leave it alone to cure up?

[kaiser]

Well they call them bulkheads, but they are just some pieces of 1" Schedule 40. You see them in the pic in the middle.

[TexasState]

Is it already drilled on the side for the bulkhead? What kind of return pump would fit in there internally? Have open the box to check to see that there's no crack or damage to the acrylic from the shipping?

[kaiser]

Ok, so here is what I decided on this. I am not going to sell it, nor am I going to return it. I would like for it to be the topic of the next Meeting. I know about the voting, but hell that can't take that darn long and from what I 've seen there seems to be quiet a bit of interest on this subject. As far as the design is concerned I was send a bunch of pieces, but nobody says we have to use them all.

[matt]

Unless the parts are cut oversize for gluing, then flushtrim, I wouldn't use it to demonstrate sump construction. (Not that I'm qualified anyway) Tim, the problem with extruded is that it has about 10% of the molecular weight of cast, and consequently absorbs much more water on the molecular level. This makes it less stable under water pressure over a given period of time. Cyro has published a pamphlet on this. Here's a quote:

"CYRO recommends that all acrylic water vessels, including aquariums should be constructed with cell cast ACRYLITE® GP acrylic sheet. This requirement exists for two reasons:
ACRYLITE® GP sheet is more capable of withstanding continuous loads than continuously manufactured or extruded sheet.
ACRYLITE® GP sheet maintains a high level of mechanical strength after water absorption has reached equilibrium.
Cemented joints must withstand the effects of the continuous hydraulic pressure and the high level of water absorption for many years. Two-part polymerizable cements are recommended for this to meet this requirement. For proper cementing techniques see Tech Brief #1-Polymerizable Cement. Solvent cements are NOT recommended.
To determine what thickness acrylic sheet should be used, the calculation below can be used assuming the base is uniformly supported."


The thing about this that really caught me was the recommendation against solvent welding, which everyone does anyway. The best pro aquarium builders typically use better quality solvents than weldon #4, though, and their joints are perfect. What I'm going to do on my next sump, though, is use polymerizing cement (weldon #40) for the bottom joint, with a channel routed in the bottom to accept the sides/end. That should be pretty bombproof. But, the only way to do something like that is to cut the bottom oversize and flushtrim.

Now, for something this small, extruded would probably hold up just fine. And people use extruded for sumps all the time; the question is, how long will they last? I honestly don't know, but since I've been taught to use cast, and apparently it will last much longer