GPH for 52 gal tank?

[rdaled]

My tank: 52 gal half hex
48"L x 12"D x 21"H

If I was to add an overflow box for a sump, how many gph should I shot for?

The only thing I plan to use my sump for is the skimmer, heater, and added flow. I'm thinking that the return(s) could be hung on each corner and run the the bottom of the tank.

With that said what size return pump should I use? Could I get enough flow from an overflow and return pump so that I could loose the PH's? I have seen that many of you have a CLS and a sump which are two different systems. I was looking to try and incorporate them together and utilize only one return pump.

Is my thinking way off base or is this doable? Pros...? Cons...?

Thanks in advance!

[Geoff]

using a sump to increase flow is generally not a good idea. the object is to keep your skimmer as efficient as possible. if you have more flow going through the sump than what the skimmer can process you have a greater percentage of unprocessed water running around the system.

CLS's are great at maintaning this efficiency while still increasing the total flow of the system. having a half hex you can add an over the back CLS fairly easily to increase the total flow in the system.

what kind of skimmer do you have, or want to have? more likely than not a Mag 7 would make a good return pump. most skimmers only process about 3-400gph.

G~

[rdaled]

My current skimmer is a HOB Remora w/ MJ1200. The MJ is rated at 295 gph but I'm not sure if this is lessened by the spray injector on the skimmer.

I understand that you feel the sump should only be running at the gph rate that the skimmer can process. But what is the difference in the unprocessed water passing up the skimmer in the sump and passing up the overflow in the display tank? Even if I have a CLS then I still can't skim at the same rate that I circulate.

I'm sure I'm mising something and want to understand this.

Thanks!

[Geoff]

unless you are planning on getting a bigger skimmer, the best option is to make a HOB CLS system. making a sump work with a HOB skimmer is difficult. matching the levels in the sump so that the skimmer will work,yet have enough room for backflow when the power goes out. it makes sump design more difficult.

the unprocessed water will then go back into the tank and increase the total DOC level in the system. extra flow going through the sump will also increase the risk of bubbles getting returned into the system from the skimmer.

G~

[rdaled]

Ok, then a HOB CLS it is. I've read that you should have 10-15 X's your tank size in GPH of circulation. Based on that I should have anywhere from 550-800 GPH. Since more is better when it comes to flow I think I'll shot for the 700-800 range. Sounds like the MAG pump is the most popular. Guess I need to start shopping for a MAG7.

Since the MAG7 has a 1/2" inlet & outlet then I guess my CLS should be constructed of 1/2" material as well... right?

Thanks for all your help Geoff!!!

[Geoff]

whoa, slow down a bit.

your thinking is correct. a little fine tuning should be done though. what kind of SB do you have? the finer the SB the bigger the outlets should be. this slows the velocity of the water down without lowering your total flow. this is good for keeping the sand from blowing all over the place. i would prolly use 3/4" tubing on the outlet side if you have a CC substrate. if you have a DSB, i would prolly use 1" tubing. 2 outlet would be good also.

as for the inlet i would use 1" regardless. the bigger the inlet the less force on the critters if they get to close.

G~

[rdaled]

I currently have CC substrate. However I was lookin to change to an oolite 1" SSB.

The picture in my mind has Charlize Theron wearing a... wait wrong picture! Sorry about that... 1 inlet at the top center of the tank and then 2 returns running down each corner with 2 outlets on each one (1 mid-way down and the other at the bottom about 2" from the substrate).

I think skeety's is similar to what I have in mind.

[rdaled]

I was visiting my parents in VA and decided to check out the LFS. Turns out they were going out of business and everything was 25% off. I scored 60 lbs of Aragalive oolite sand, (2) CLS returns, a mag float cleaner, and 10 lbs of base rock all for $75.00!! The guy ended up giving me like 45% off.
Goodbye CC, Hello LS!

I am also building a DIY canopy which will incorporate a shelf approxiamtely 6"-8" below the top of the tank for the CLS to sit on. So what size pump should I go with for the CLS? The inlet will be 1" pvc with a T at the intake. The outlets are 1/2" with adjustable nozzles (picture attached). With the smaller outlets I'm sure the water flow will be more concentrated so I don't want to overdo it on size of pump. I am thinking Mag5 since I will be losing very little to head pressure.

Thoughts???

[Geoff]

adjustable nozzles like that work great for breaking up the water surface.

G~

[rdaled]

I was planning on pointing them down towards my LR. IYO will I need additional outlets to go along with these or should they provide suffcient flow for my 52 gal by themselves?

I'm trying to decide whether to order the Mag5 or 7 to run my CLS.

[Geoff]

with a DSB and thin nozzles like that you will have a hard time keeping the sand still if you point those down, but it is worth a try. what kind of corals are you planning? that would be a lot of velocity at any corals, SPS can handle higher velocities than softies/LPS, but even they can only handle so much. adding more outlets would be great if you can. this will only work if you can divide the outlets right were the pipe changes size.

G~

[Doug1]

Water velocity and oolitic sand beds are usually problematic to reach a happy medium with. The sugar sand tends to blow all over , thats why a lotta reefers use the raised rock/spraybar under it technique, it helps keep muck from accumulaing under the live rock and causing problems.

Flow rates for water in system recommendations (ie 10x, etc) are in my opinion like wat6ts per gallons ratings, pretty meaningless without considering the whole dynamic of the system, and the biotope being emulated.
In your case you have a 52g tank that prolly has around 40 g water in it after the rock and sand displace water, so if you add a typical single 1" drain overflow box, that will drain approx 400 gal per hr, so in theory you are at about 10x flow rate, assuming that your over flow is working at near maximum, but then when you add water volume to the sump, then the flow rate falls below 10x, is this a bad thing, no, not at all, your water will still go thru the overflow, drain into sump and return to the main tank at the same rate, that is @ X gallons per hour.
Changing the size of the sump, and using the same overflow box and return pump, the flow thru rate will stay the same, the flow factor will change as its gallons per hour vs volume.
If the overflow drains 400 gph and the return pump is pumping 400 gph then the flow rate thru the system is 400 gph, it doesnt matter if the sump is 10, or a 100 gallon Rubbermaid stock tub.
What does change is the velocity thru the sump, the smaller the sump, the faster water will travel from to input(drain) side to the output (return pump) side
This has 2 noticable effects, the faster water goes thru sump the more noise and potential for micro bubbles, as well as more salt creep potential.
If you splurge and get one of the upscale dual 1" drain overflows and a correspondly larger pump, you can get double the flow rate thru the system, along with higher noise levels from the overflow box, water pouring into the sump, all that sort of thing
Hope that helped you visualize whats going on and not confused you

Geoff and i both hold to the theory that having all the water, or close to it, going thru the sump being processed by the skimmer is a good thing, its about efficiency.
Your Remora is prolly pushing less that 295 gph thru the skimmer, not sure what the efficiancy rate of their design is, but lets say it actually processes 200 gph hanging on the back of the tank. That means that theoretically you are skimming the water in the tank 4x times an hr, assuming that you have enough movement that its not sucking in skimmed water that just poured back into the tank. Since its captive in the tank, eventually it will all get skimmed at somepoint, hopefuly at a rate that not be overcome by live rock shedding, fish waste, feeding, etc.

[rdaled]

I am only planning on a 1" or less SB. I'm not sure yet on the exact corals I will be keeping. However I do know I will at least have softies and LPS.

So what exactly do you mean by "divide the outlets exactly where the pipe changes size"?

Thanks again Geoff for all your advice!

[rdaled]

Confused? I have been confused since day 1. There are way more variables to saltwater than I ever thought possible.

Here's what my plans are (pending advice):

I currently have my system torn down and am cycling 35lbs of LR in a 10 gal glass tank which I plan to use as my sump when I set back up. I also have my Remora skimmer w/ MJ1200 running on the side of the 10 gal. It works perfect with the sump tank completely full of water and hangs on the outside. Once I set it up as a sump I plan to lengthen the adapter hose from the MJ to the skimmer so that the MJ sits on the bottom of the sump. That way I can run the skimmer on the outside of the sump and it still only be 1/3 full. The only other items that will be in my sump are a heater and return pump. I was looking to put an 300gph overflow on the display tank to feed the sump and a Mag7 pump with a flow valve to return the water to the tank.

I will also have a HOB CLS with probably a Mag5 pump.

So those are my "plans" as of right now. Please steer me in the right direction if I am way off in left field.

Thanks Doug!

[Doug1]

OK I have included(I hope) a simplistic sump drawing showing the wier and seperate return pump chamber, the skimmer with hose extention to pump is represented in the middle. Putting the divider in allows you to run a higher water level in the sump and still allow for minimal drain down, you can control the water depth in the return pump section by adding more or less water as you need. The empty area above the wier is what you have to contain the water that drains down into the sump when the power to the return pump is off. Thats why its important to use a siphon break hole on the return line just below the water line in the display tank so that you have minally backflow