overflow, filter and pump size

[ellisz]

I have the outside box of an overflow from an amiracle system. I am going to make an internal box with a Lee's specimen box. I got the plans off the internet Anyone try this?

I was also wondering about the return pump size. Is there a minium pump size I will need? The drain on the overflow is a standard size, I believe. I think it is 1". It uses the big accordion style hose. It is for a 29 gal tank that will house a porcupine puffer and LR(maybe).

If I can get enough LR, I will go that route for filtration but I might just use some base rock to keep cost down. If I use base rock, I will use bio balls. I want to make sure the water going out will not be too slow vs the draining water coming in.

Thanks

 

[loganj]

Why use the bio balls if you have base rock? The bacteria will culture the base rock as quickly as it would th bio balls...assuming you have enough rock in there. If you put all base rock in there and top it off with a few good pieces of LR, it will all be LR eventually. JMHO.

I'm thinking you should be able to do 500 gph with that overflow depending on what size siphons you use. I'm guessing you'll be limited to either one 1 1/4 U tube or two 3/4 U tubes. Either way, it should do it. I'm thinking maybe a Mag 5 or, probably better, a Mag 7 would be what you need. Better to have a little too much pump and valve it down some than not enough pump.

 

[ellisz]

I have heard that you could use base rock and seed it with LR but I figured since that would be my filtration I would have to have the base rock seeded before it would be effective enough to have fish in the tank. Is this wrong? Would I need to run some other kind of filtration while the base rock is converted? I had heard that it can take months to make base rock LR.

On the U tube, it is a 1 1/4. Being that this is for a small tank and water flow could be achieved with a couple of power heads, would a big PH work vs. the big mag drive pump? I think I can get a Mag easily but I only use a Mag 7 on my 75 gal tank. Would the overflow be flowing so much water that a Mag 5 would be needed?

Thanks

 

[loganj]

Yes, it does take months to make base rock into colorful, coraline covered LR. The nitrifying bacteria will grow on it as quickly as it would on anything else though. I don't think that will cause you a problem as long as you have enough rock in the tank.
Again, yes, you can use a powerhead to return water to the tank. I have a couple of coral prop tanks that use Maxi Jet 1200's for return pumps. The top tanks are 20 longs that are drilled in the bottom and will only accomodate a 1/2" drain. If I had larger holes in them, I would probably up the flow between the upper and lower tanks. Here are two problems with very low flow through an overflow. The first and least likely problem is that the low flow through the large U tube (1 1/4" wasn't it?) will not carry the occasional air bubble on through. The bubbles will get trapped in the top of the U and will stay there. This can eventually lead to losing the siphon if the bubbles are allowed to build up in there. You may or may not have problems with this. I would probably use a smaller tube if I was going to have low flow through the overflow...maybe a 3/4"...because it will increase the velocity in the U tube and should carry the air bubbles on through. The second problem with low flow is that although you will be skimming water from the surface, there won't be enough current in the inside box to carry the DOC's through the U tube. This may result in DOC's accumulating both in the inner box and on the surface of the tank. I hope this makes some sense.

 

[ellisz]

Alright, I got my internal overflow box done last night. Hopefully it will work. It is probably a 1/4 the size of the outside box.

Couple of questions left ....
***BTW, this got long. If there is a website that details this, please tell me. I did not mean to make this that long in the beginning ...

The instructions I have for the overflow build say to drill a hole in the U tube and put some tubing in it to start the siphon. Is this the best way for this? I don't see this on some of the ones for sale.

As for function, the holes in the internal box skim the surface of the water and when the return pump goes off, the water level drops and the internal box will be emptied(or mostly) and the siphon will break. Would it be better to extend the drain up on the outside box to limit what will drain to the sump? The plans I have say to put a 90 elbow on the drain to reduce noise of the drain.

If the siphon is broke but the pump stays on, what is done to prevent the tank from overflowing? My other tank has an internal so I don't worry about this.

On the water return, does this have to be anything special? I have some PVC fittings that came with the overflow that are U shaped that I think will work. The one thing I noticed is that there is a small hole in one of the fittings. This is also on the return line for my internal overflow. Does this need to be under water?

For the water going into the sump, I have seen people that put some kind of baffle to stop micro bubbles from getting put in the display tank. Are there any tricks to running the drain hose from the overflow into the sump. Can I just place it into the sump under the water?

Sorry for all the ?'s but I think that does it.

 

[loganj]

Alright, I got my internal overflow box done last night. Hopefully it will work. It is probably a 1/4 the size of the outside box.

Couple of questions left ....
***BTW, this got long. If there is a website that details this, please tell me. I did not mean to make this that long in the beginning ...

The instructions I have for the overflow build say to drill a hole in the U tube and put some tubing in it to start the siphon. Is this the best way for this? I don't see this on some of the ones for sale.

I would not do this unless you intend to glue a piece of air line sized acrylic in the hole and hook it to the venturi on a strong powerhead. Thread a piece of air line tubing up into the U tube to the highest point in the U and suction the air out.

As for function, the holes in the internal box skim the surface of the water and when the return pump goes off, the water level drops and the internal box will be emptied(or mostly) and the siphon will break. Would it be better to extend the drain up on the outside box to limit what will drain to the sump? The plans I have say to put a 90 elbow on the drain to reduce noise of the drain.

Yes, you need to extend the drain pipe in the external overflow so that the water level will stay high enough to prevent breaking the siphon. Although I don't have the link handy, check out Richard Durso's page for plans on a quiet drain. I have a similar setup on one of my tanks and it works quite well.

If the siphon is broke but the pump stays on, what is done to prevent the tank from overflowing? My other tank has an internal so I don't worry about this.

Absolutely nothing. If the siphon breaks and the pump is still running, the contents of the sump will be in the floor.

On the water return, does this have to be anything special? I have some PVC fittings that came with the overflow that are U shaped that I think will work. The one thing I noticed is that there is a small hole in one of the fittings. This is also on the return line for my internal overflow. Does this need to be under water?

It should be just barely under water. You don't want it spraying on the surface as this will create excessive salt creep. The purpose of this hole is to create a siphon break on the pump side. If the pump quits, water is going to siphon back down the return line through the pump and into the sump. If you don't have an air hole to break this siphon, the tank will empty down to the level of the return line in the tank. With the air hole, the siphon will be broken when the water level reaches the hole in the return line. I'd have it at or just under the level of the internal overflow. You'll want to test this to make sure the sump will hold the drainback in case of a pump failure.

For the water going into the sump, I have seen people that put some kind of baffle to stop micro bubbles from getting put in the display tank. Are there any tricks to running the drain hose from the overflow into the sump. Can I just place it into the sump under the water?

Sorry for all the ?'s but I think that does it.

Most folks put the return as deep in the sump as they can I think. With the flow levels you're talking about, I don't think you'll have any trouble with bubbles. You can always add baffles later if you need to. You might want to put a shield of some sort around the return where it goes into the sump. I used the tops off freezer containers on mine. What this does is lessen the salt creep from the bubbles breaking on the surface right around the return line. It really made a big difference for me. HTH 8)

 

[ellisz]

That helps tremendously. Thanks alot!

 

[ellisz]

BTW, I tested the overflow last night. Worked pretty good and now I understand it a lot better

I plugged the hole in the second chamber last night so I will test it again tonight. Only thing I wonder about is the size of the outside box. It does not matter if it is alot bigger than the inside box does it? I have even considered buying the bigger speciman box for the outside box but I would rather spend money else where

I tested it using a 802 PH but it is definately not big enough. Got to get a MAG now.

Keeping the return in the tank stable and keeping salt creep on the wall from the overflow are my next concerns ...

 

[loganj]

The size of the outside box doesn't really matter as long as it's large enough. Sounds like you're on the right track to having a functional overflow setup.

 

[RandyStacyE]

Personally, I hate the thought of a syphon overflow. I set up my glass 55 gal aquarium with the thought that I could always make improvements to it later. I now know the most important factor was surface skimming and a sump was the key to easy maintenance. I should have had my glass cut/drilled to install a bulkhead fitting. I wish I had an internal overflow in the worst way.