Hang-On overflow for 2ft tank

[Ken_ng]

Dear reefers

Anyone has a recommendation on a hang-on overflow for a two 2tank?

1) Where to buy?

2) what return pump should I pair it with?

3) how much roughly?

First time trying to setup a sump. Please drop me some pointers.

Appreciate all.

Many thanks

[xeneryx]

whats a two 2tank bro ?

anw u can get it from aquamarin.

skimz.

return pump can depends on your volume of the tank

[Ken_ng]

2 feet tank I'm sorry..

Yeah I saw the skimz one. It's a monster.. I think that's too big leh bro lol.

How to know which pump is sufficient? As in measure the flow rate?

[tofubox]

Correct me if im wrong guys. But i think its more about the turn over rate when it comes to the return pump. Of coz the pump also adds to the flow rate overall. But what u want is to turn over the total volume of your tank at like 20 times or something along that line every hour. So calculate your tank's vol, than multiply that number by the amount of turn over you require. That should give you the return pump rate.

With regards to the external overflow. u need to ensure it can handle the flow rate of your return pump. Also allow plenty of room for error, i.e buying a larger than required overflow box. This prevent normal overflow situations. As for clogged overflow, thats another story.

[Tian85]

overflow rate should be around 7 to 10 time of your total volume will be good.

The rest of the flow should come from your wave maker.

[Ken_ng]

Thanks guys!

I have read that a hang-on overflow is like a ticking time bomb because if the siphon breaks, the main tank is going to overflow..

If the pump breaks down the sump is going to overflow.

The second senario not as scary because if there is sufficient margin, the siphon would break after the level drops below the overflow level..

But for the first case, is there any preventive action possible?

So based on the response, I should get a pump then pair my overflow to it as a reference and not the other way. Am I right?

[Boonboy]

My 2 cents worth...

I am using a hang on back overflow (skimz).

It had never broke siphon (for me) but had observed there were air pockets inside the siphon area. Managed to remove the air pocket before the siphon was broken.

How did the air get in there? The water entering the overflow box cause bubbles to form. These bubbles got trapped in the siphon area. Resolution? I raised the water level in the overflow box by reducing the water leaving it (turning the knob) above the durso. Doing so the water entering the overflow box did not create bubbles that could enter the siphon area.

Thinking this solved my problem? Wrong this was when the nightmare began!

Apparently, the water flow leaving the overflow box was lesser then my return pump flow. This did not happened immediately but over some time. (Maybe my return pump powered up) It happened when I'm not home. You know what happens next...

Yes... Flooding!

What next? Determined to make the overflow box work... I tried other way to stop the bubbles. This time I added a net(like a fish guard) at the water entrance to the overflow. It helped! Unfortunately, I did not secure it and it floated away(again when I was not home). Fortunately, it did not cause flooding as it needed many hours before the siphon is broken.

Long story short, I am checking the overflow box twice a day to ensure it is okay. (Free of trapped air)

Conclusion, drill hole in your tank for the overflow if you want peace of mind. Btw I am still using the hang on back as I am already used to it.

[Jameshong]

Hi bro,

Why not mod your bare tank to IOS by using acrylic sheet? Plan, design and pre-cut by Dama. If your tank is acrylic, weld it with acrylic glue else for glass tank, use aquarium silicon to bond it.

FYI, when I started my reefing 10 years old, I diyed my IOS box that similar to Jireh's quick start system which work quite well for >2ft tank but same as all nano tank, need frequent water change to maintain all water parameter in good condition.

[Jameshong]

Hi bro,

Why not mod your bare tank to IOS by using acrylic sheet? Plan, design and pre-cut by Dama. If your tank is acrylic, weld it with acrylic glue else for glass tank, use aquarium silicon to bond it.

FYI, when I started my reefing 10 years old, I diyed my IOS box that similar to Jireh's quick start system which work quite well for >2ft tank but same as all nano tank, need frequent water change to maintain all water parameter in good condition.

If you are serious into reefing hobby but budget constraint for new iOS or sump tank, you can search around pasar malam thread which sometime can get very good deal....

[Ken_ng]

Thanks bro boonboy and jameshong for the valuable input!

I managed to get a good deal recently. A 2ft sump tank for a reasonable price.

That's why I'm planning to convert my canister on the 2ft to a sump.

I know a 2ft DT with 2ft sump is ridiculous but no choice..

That's why deciding on an overflow box and a return pump.

Just worried that the overflow box siphon breaks and DT overflow. That would be disastrous. Thts why seeking the shifus advice here..

[Land2013]

You may try diy overflow pipe. I using now and there is no concern of siphon break as l tested multiple time. 2ft sump will not be very big after u put in skimmer, fr, media, refugium and returm pump.

[tunicate]

Hi Ken,

If you use an HOB overflow box, you're right to worry about breaking siphon. The risk increases when using an oversize box which the return pump could not provide optimum flow.

The 2nd scenario applies to both HOB overflow box & built-in overflow. We generally build the sump bigger to accommodate the extra volume during power outage.

The extra volume is actually adjustable depending on the depth of your return outlet in the DT.

Thanks guys!
I have read that a hang-on overflow is like a ticking time bomb because if the siphon breaks, the main tank is going to overflow..
If the pump breaks down the sump is going to overflow.
The second senario not as scary because if there is sufficient margin, the siphon would break after the level drops below the overflow level..
But for the first case, is there any preventive action possible?

So based on the response, I should get a pump then pair my overflow to it as a reference and not the other way. Am I right?

[drato11]

I've been using HOB overflow box for about 2 years. So far no problem and happy with it as my current tank doesn't come with drilled overflow holes.

Imo, the air-pockets will only be formed in the overflow box if the return pump is too weak. Then, the bubbles entering the overflow box will not have enough movement to be sucked out of the box, causing air pockets to be formed. I'm using an adjustable return pump. When i adjust the flow too low, i can see air pockets slowly forming in the overflow box. Once i adjust the flow slightly higher, I can see the air bubbles all get sucked away from the box. So it's important to match your return pump flow with the overflow box capacity. Getting too big a box, without a strong enough return pump will cause air pockets to slowly build up.

[Evolutionz]

Try to find old-style u-tube type of overflow. The new kind which skimz is using are very problematic. I'm using a brand less u-tube overflow box and for 8month never did it once break siphon or give me any problems at all. Look into eshopps. I believe they uses u tube style.

[p.tm]

Hi bro if you have time you can consider a diy overflow. Its a lot cheaper

[Clement Chen]

How much is e skimz overflow? If it is around $100 might as well make a new tank that is drilled. Its around that price

[p.tm]

Yea agreed with clementC bro.. not worth the money for an overflow imo

[Ken_ng]

Thank you all the seniors for the feed back..

Please correct me if I'm wrong..

1) get the traditional u shaped overflow boxes that is the most reliable

2) if the box is about $100, better to make a new tank

3) bubbles accumulate because of insufficient flow. So I should overpower my return pump and use a ball valve for flow regulation.

4) diy overflow pipes are cheap and easy to do

Questions:

A) Would bro land2013 or p.tm be able to give me a rough guide on how wide and long the PVC pipes should be?

where to get PVC pipes and how do I prevent a loss of siphon in the PVC pipes?

C) would eheim pipes work?

Thank you very much everyone!

[tunicate]

Another option would be to have someone drop by your place to drill a proper overflow hole(provided the glass is not tempered). You can give Aquarium Artist a call for a quick quote. He can probably provide you with a proper overflow box & plumbing if you want, otherwise, you can diy those.

[Land2013]

You can search this forum for the diy pipe. Im using 20mm overflow and 16mm return. The length need to measure ur tank height. The siphon will not break using pipe but very noisy. I buy a valve to control and its completely silent. I pm you the photo of mine tonight for some guide but u better read more to understand. Pipe and connector can buy from normal hardware shop.I ever consider drill hole but is abt $70 exclude piping or corner box which easily more than $150 and you also need to add turso piping to reduce noise level.

[p.tm]

You can search this forum for the diy pipe. Im using 20mm overflow and 16mm return. The length need to measure ur tank height. The siphon will not break using pipe but very noisy. I buy a valve to control and its completely silent. I pm you the photo of mine tonight for some guide but u better read more to understand. Pipe and connector can buy from normal hardware shop.I ever consider drill hole but is abt $70 exclude piping or corner box which easily more than $150 and you also need to add turso piping to reduce noise level.

+1 here's a nice link to start with: www.youtube.com/watch?v=65yVr7DiDls

[Ken_ng]

I took the plunge and went for it today!

I bought 5.5feet of PVC pipes and a whole bunch of elbows.

Cut everything using a PVC cutter which I got for $8 bucks and glued everything together with PVC cement.

Total Cost including glue and cutter is about $21. That's a fraction compared to the cost of an overflow box.

It's curing now but I must say it's not difficult to do..

Will do a leak test once I get the time. Thank you very much everyone for giving me the advice which I needed..

I've got some other questions now:

a) how do I drill the hole for the check valve and air line? Is it necessary?

if I'm using a 1/2" pipe, what size of hose should I get and what about the return size?

c) how do I I fix the ball valve to the pipe? The pipe seems loose in te ball valve. It's the right size I have double checked.

c) I searched and estimate that the 1/2" inch overflow would generate about 300+ GPH after losses. I am planning to tee off the return to my chiller and the skimmer compartment of my sump once more. What size of return pump should I be getting? Should I get and external or internal pump?

Thank you everyone once more!

[megacue]

I using eheim 1260 in my 2ft, return from sump to chiller then main tank, w/o tee off. Find insufficient flow and likely to upgrade. As for the airline is to kick start the priming/siphoning. 13mm ball valve should be using a thread/slip in adapter, cement glue it to pipe should be ok. Attached a picture for better understandinh.

Sent from my SM-N9005 using Tapatalk

[Ken_ng]

Bro megacue!

Thanks for the pointer. Guess we would need a more powerful pump than that.

Any pumps to recommend?

[artxakis]

hi bro

im using a skimz oveflow box with a 2000lph return pump. i think anything lower also no problem but to be safe i use a cheap dosing pump to provide constant suction pressure