Freshwater Sump?

[Yao]

I know people have sumps for saltwater tanks, because you can put live rock and have a protein skimmer in there, and it won't take up room in your display tank. Would it be too excessive to have a sump for a freshwater tank? I am purchasing a 55 gallon next month, which I know isn't even that large. But I'm really attracted to the idea of having small (10 gallon?) sump for this tank, because from what I understand, it's an automatic top-off, and easier on water changes, and I can just store a wet/dry filter in there. Correct me if I'm wrong. Do people do this, or should I just use a regular filter? Also, since it's for a freshwater tank, I wouldn't need a protein skimmer or anything... so would my sump need to have any compartments? I've only read about and seem plans for saltwater tanks. So a freshwater sump would be really simple to build I think, but can someone tell me if I'm thinking along the right lines?
8O

 

[fishfreek]

no way would it be excessive. You can put your heaters in the sump as well as if you have hang on filters you can hang them on your sump instead to have a less cluttered main tank.

sumps ease water changes in that you can just shut off the pump. drain the water from the sump. Add new water to the sump to the same water line the sump had before you drained it and then power up the pump. water change done.

I would suggest something larger than 10 gal. The reason is evaporation. You can expect up to 1 gal of evap per day from a sump setup on a 55 gal. You cant run the sump at full capacity (10 gal of water) because you must provide some room for backflow when the pump is off as water will flow out of the tank to some degree into the sump. This means your sump will most likly run with a max of 5-6 gal of water in it. Since most pumps pickup above the bottom of the tank a few inches this gives you something like 3 gal of acutal evaporation room. (the pumps used to return water will cause a vortex kind of action when the water level is close to their inlet so water must be an inch or more above the inlet to keep air from being injected into the system).

This would give you at max 3 days between topoffs of the sump. If you upgrade to say a 15 or 20 gal tub for the sump you can get up to a week between having to add additional freshwater to the system to replentish evaporation.

You cant put a wet/dry filter in the sump but the wet/dry filter itself is a kind of sump. The wet part of the filter is the sump and the dry part where the water trickles over the bioballs is the filtration.

The skimmer will not work on freshwater so there is no need.

 

[Yao]

I've read the postings about sumps on Melev's Reef website and the posting under the sticky in this DIY section... but they are all for salt water tanks, and all include protein skimmers and a fuge.
If I were to build a 20 gallon sump using an all glass tank, would I be able to do what RLG2182 did in his 40 gallon sump project by using a 20 gallon tank, glass pieces for a baffle, pipes and a return pump? Do I need to make a special compartment to hang on back of the tank for water to flow over into the sump, or is there another way to do it with just pipes...?
Are return pumps (I think that's what they're called) expensive?

 

[fishfreek]

You dont have to compartmentilize the sump at all if you dont want. The concept of the sections is to provide bubble traps and also to provide distinct areas for specific purposes. There is no requirement to have different sections.

If you dont want to segment the sump you dont have to. Just put the tank drain on one end and the return pump on the other end. Put your hang on anywhere you want and the heaters in the bottom of the sump.

The pumps will range inp rice from $50-$150 depending on the capacity. Since you can size the pump so as you dont need any other form of water circulation in the main tank this is often cheaper than having a few powerheads, etc.

When sizing your pump always know the capacity of the overflow your going to use and never buy a pump that pushes more water at the given headheight you have than your overflow will process.

 

[Yao]

Not having to make compartments would be wonderful. Just out of curiosity, what's the purpose of a bubble trap?

Is there another way to have an overflow from the tank, or do I have to build an overflow box, like this: http://www.melevsreef.com/acrylics/overflow.html?

How do I determine the capacity of the overflow?

Thanks for all your help!

 

[fishfreek]

The concept of a bubble trap really falls onto the skimmer in saltwater. You want the chamber that the skimmer is setting to not have bubbles in the water itself as this will affect the intake of the skimmer. In addition there is often a bubble trap before the last chamber so as to keep from injecting bubbles back into the tank thru the return pump. But if your sump is long enough and you have the sump drain and the sump return on opposite sides this often isnt an issue.

You can get hang on overflows. I prefer the "U" tube ones they can be found at http://www.lifereef.com The ones with a single drain are often 700GPH capacity and the ones with two are often 1400GPH speed. there are C channel overflows made by CPR but I dont really like them much as compared to the U tube models.

 

[czcz]

As fishfreek said, a traditional wet/dry is all the sump you need for your application. Here is my old howto, fwiw. I stuck plants in there and lit it off a desklamp because it was easy and let me breed shrimp. Here is a good site with many wet/dry plans (currently down). Here is an old pic of jsoong's very clever layout. Goldie boards can have very interesting FW sump plans, but you should DIY/borrow the parts of SW sumps you find interesting, excluding unnecessary stuff like bubble traps and skimmers and such. HTH

 

[Yao]

Thanks! Your posts have been very helpful. I am debating on getting an oveflow box from MarineDepot or building my own by following the directions on Melev's Reef. I will probably use the 20 gallon long (not making compartments) I currently have for a sump to fit underneath the 55 gallon I will be getting next month. Depending on whether I build my own or buy an overflow and the GPH speed, I'll get either the MagDrive 3 or MagDrive7 powerhead. Please let me know if there are any more suggestions! I will update with what I end up doing, especially if I DIY the overflow box!

 

[Yao]

I'm doing some research on buying acrylic from local plastic dealers, and came across a question. I thought I've read on here before that you never wanted to use plexiglass because it can become yellow and brittle, and will not last; and that you should use acrylic for aquariums, sumps, etc. However, I was told today that acrylic and plexiglass are one and the same. Is this true? I didn't think I would be able to bend plexiglass to make my overflow box... can someone explain the difference/same-ness to me?

 

[jsoong]

What you want for aquarium is "cell-casted" acrylics - as opposed to cheaper extruded acrylics (such as plexiglass). There are different brands of cell-casted, just ask for it at your plastics place. Plexiglass is a brand name, but is often used generically to mean all acrylics. <Like Kleenex for all tissues.>

For an overflow, I don't think cell casted is absolutely necessary ..... The whole thing is under pretty low pressure so don't require high strength. And even if it developes small cracks & cloud over (it will over time) it is hidden so will not be unsightly.