Overflow types

lIghty

Purple Tang
Joined
3 Nov 2007
Posts
5,052
Reaction score
53
Location
Westville, Durban
Hi, what exactly is a c2c overflow, is it a tank with 2 overflows in each corner and does it 'skim' the length of the tank??? what other types of overflows are there?
 

Marinemagic

Member
Joined
6 May 2007
Posts
86
Reaction score
1
Location
Cape Town
hi there, have a look at my tank setup, I have got a c2c with one overflow box, but you can have it with two overflows. The most important thing about it is that the lenght of the overflow must be 100% level.
1547616d6a289ce.jpg


1547616d6a3d1d2.jpg


15477761707d845.jpg
 

lIghty

Purple Tang
Joined
3 Nov 2007
Posts
5,052
Reaction score
53
Location
Westville, Durban
Marinemagic, I see what you mean, 1. Does it help to skim a bigger area? 2, Is there not a risk of fish jumping over into it?
 

Kanga

Retired Moderator
Joined
7 May 2007
Posts
4,576
Reaction score
23
Location
In the Koeberg blast radius
Marinemagic, I see what you mean, 1. Does it help to skim a bigger area? 2, Is there not a risk of fish jumping over into it?
Certaily is a benefit in having a larger surface skimmimg area.

You can use eggcrate or an overflow comb to stop fish from going over
 

Marinemagic

Member
Joined
6 May 2007
Posts
86
Reaction score
1
Location
Cape Town
Yes there is a risk of fish taking a swim, but I will be putting up egg crate to stop them from doing that, as well as the snails crawling over. The experts say that the larger the surface skimming the better your skimmer will work, I will wait and see as my other tank does not have this setup, but is alot smaller.
 

lIghty

Purple Tang
Joined
3 Nov 2007
Posts
5,052
Reaction score
53
Location
Westville, Durban
Marinemagic, I see you got pipes in you over flow, 2x drain and 2x return??

I'm busy designing my new 5ft and was thinking of putting 3 pipes in, 1x drain 1x return & 1x for electrical cables so they can't be seen running up behind the tank,(making things neater)

any advise??????
 

Marinemagic

Member
Joined
6 May 2007
Posts
86
Reaction score
1
Location
Cape Town
yes I have seen this done before, just remember the pipe for electrics has to be big enough to fit the plug thru otherwise you will have to cut the plug off and then you will lose the guaranteeon new pumps. Also most pumps do not have long enough electric cords so you will have to cut and lengthen them. Also if you go for one overflow box you will still have to run a cord to the opposite side.
 

lIghty

Purple Tang
Joined
3 Nov 2007
Posts
5,052
Reaction score
53
Location
Westville, Durban
yes I have seen this done before, just remember the pipe for electrics has to be big enough to fit the plug thru otherwise you will have to cut the plug off and then you will lose the guaranteeon new pumps. Also most pumps do not have long enough electric cords so you will have to cut and lengthen them. Also if you go for one overflow box you will still have to run a cord to the opposite side.

Thanks for you input. Was thinking of just running main feed lines up and have a insulated "DB" in the canopy, therefore the lights and pump cables would just run in the canopy. You think this is good?
 

phat

Chromis
Joined
6 May 2007
Posts
745
Reaction score
2
Location
the slums
The experts say that the larger the surface skimming the better your skimmer will work
agreed but what has been left out here is that it depends on the amount of flow going over your overflow, C2C allows for alot more turnover through your sump if you have plumbing that can handle,

look at it like this, you are essentially wanting to skim the water just below your water surface...

take a weir 10cm long and pump 1000l of water per hour over it
then take a weir 100cm long and pump 1000l of per hour over it

what difference are you gonna get?

the height of the water going over the weir not so, (have never measured the difference) lets say on 10cm weir you get 1cm of water height flowing over it

and on the 100cm weir you 0.5cm water height flowing over it

which is giving your skimmer more surface water?
 

DragonReef

Yellow Tang
Joined
4 May 2007
Posts
2,600
Reaction score
2
Location
Durban, ZA
Mmm Phat, sort of but not really.

Your sump turnover will be determined by the size of your return pump and the size of your drain pipe. A 12000L an hour return pump draining through 2 x 50mm pipes and you will be turning over a whack load of water through your sump. But doing this doesn't necessarily mean that you are exporting that much more waste to your sump / skimmer.

Your skimmer will only be as efficient as the amount of DOC's that you are able to export from your system. By having a single corner overflow, it minimises your chances of being able to get the waste out of your tank. Powerheads / closed loops etc will push waste away from the overflow most times, or you find that you are setting flow up to be able to utilise the overflow and compromise coral health.

With a coast to coast you are virtually skimming the entire surface of the tank, which greatly improves the chances of getting the protein waste out of the tank and into the sump where your skimmer can pick it up.
 

phat

Chromis
Joined
6 May 2007
Posts
745
Reaction score
2
Location
the slums
all of that agreed

Mmm Phat, sort of but not really.
except that if you are not getting your DOC's to the skimmer cause you have a really large overflow and minimal water trickling over it (guys always suggest 10X tank volume for turn over for sump flow) at 10X tank volume it renders C2C pointless as much isn't getting surface skimmed so your skimmer is not getting them DOC's, the higher your water height over your weir depicts hw much you really can get to your skimmer, ever heard of back pressure?
 

phat

Chromis
Joined
6 May 2007
Posts
745
Reaction score
2
Location
the slums
By having a single corner overflow, it minimises your chances of being able to get the waste out of your tank
agreed i am saying that to large of an over flow can also be as bad as to small

Powerheads / closed loops etc will push waste away from the overflow most times
well em anthony thats why plan ahead;)

or you find that you are setting flow up to be able to utilise the overflow and compromise coral health.
flow that comprimises coral heath?

With a coast to coast you are virtually skimming the entire surface of the tank, which greatly improves the chances of getting the protein waste out of the tank and into the sump where your skimmer can pick it up.

agreed but pretty pointless if you dont have enough flow going over your C2C to surface skim properly
 

DragonReef

Yellow Tang
Joined
4 May 2007
Posts
2,600
Reaction score
2
Location
Durban, ZA
Back pressure on what ?

Setting up flow in your tank to direct water to your overflow as a priority, as opposed to using your power heads to direct waste to and from coral. This will compromise health.

It goes without saying that regardless of the type of overflow you design, your drain plumbing and return pump need to be able to cope with it.
 

phat

Chromis
Joined
6 May 2007
Posts
745
Reaction score
2
Location
the slums
It goes without saying that regardless of the type of overflow you design, your drain plumbing and return pump need to be able to cope with it.
you missed the boat and surface skimming(which is what overflows play a bbig role in is whats this is about which also plumbing has alot to do with:p) and go do a search on google for back pressure
 

Kanga

Retired Moderator
Joined
7 May 2007
Posts
4,576
Reaction score
23
Location
In the Koeberg blast radius
The oil film/scumline that you sometimes see on the surface of some tanks is the DOC's. the bigger the wier/overflow the more of these DOC's you will be sending to you skimmer more often. Clearly this is a good thing.

Phat as for back pressure, between the overflow and skimmer the only backpressure you will get is from too many bends or valves in your piping, however if your overflow copes with the water volume, then it will have no effect on your surface skimming, if it doesn't, get a mop ready. :D

HTH
 

Ridwaan

Regal Tang
Joined
8 May 2007
Posts
3,033
Reaction score
108
When i had a normal overflow,i always experienced this oily dusty layer on the surface of the water and when i changed to c2c i never experienced this again,also,my skimmer performed better.
 

Kanga

Retired Moderator
Joined
7 May 2007
Posts
4,576
Reaction score
23
Location
In the Koeberg blast radius
When i had a normal overflow,i always experienced this oily dusty layer on the surface of the water and when i changed to c2c i never experienced this again,also,my skimmer performed better.
And that sir is the bottom line, would you not want the same for your tank??, thanks Ridwaan
 
Last edited:

Similar threads


Top