Help a Newbie With Overflow Flow Questions

[robsee06]

Hi Everybody,

I am in the planning stages of settign up a 120 gallon (48x24x24) reef setup. I am having a tank built so the choice of where to drill the holes, locate the sump, etc. are up to me. I have been doing alot of reading but would like some specific answers to my particular setup. Any advice would be appreciated.

1. It is my understanding there should be 5-6 times tank volume circulation per hour. Is this correct?

2. I plan to have 2 built in overflows installed. One in each corner of the tank. I plan these to be 6"x6". Is this an appropriate size? I want two overflows because I travel alot and want a "backup" in case of a clog.

3. I am trying to determine what size PVC to use for supply and return (I will be using typical "sump" arrangement with tank on "typical" stand with sump underneath). Since I need roughly 700(?) gph circulation total do I want the ability to do 350 gph from each overflow or 700gph from each overflow (i.e. if one overflow clogs can I run the whole system off the other)? Depending on which case it is above, what size PVC should I use for supply and return. I was thinking 1.5" for supply and 1" for return. Is this too large because I am using two overflows or is it really regulated by the rate of return of the pump itself?

4. As for the returns, I think 2 would be best...right? Is it better to have them come back up the from the bottom through the overflow boxes or should I have holes drilled on the back of the tank?

5. I am also having holes drilled for a CLS. Does adding a CLS affect any of the issues above. For example, because I am adding a CLS can I get away with less hourly flow to the sump?

I understand all that stuff about head pressure and pump size but I want to make sure that I get the proper holes drilled and the proper overfow installed. So lets start with these questions for now.

First time posting, but long time reading...you guys have a great site...Thanks in advance.

[Doug1]

Go with 1" bulkheads and plumbing from your overflows, with durso or stockman mods to quiet it down you are still looking at well over 400 gph per overflow, so you will have a lot of safety margin with a return rate of 700gph

I would do the returns over the top rather than drill them, that gives you more flexibility fpr placement

If you do a closed loop, you can add a lot more flow without the noise issues with high volume through the sump

[Geoff]

Welcome to TRT!!! longtime luker.



i believe in only running the same amount of water through a sump as what your skimmer can process. this is generally around 400gph. with dual overflows if you get a monster skimmer later than you have plenty of head room to grow.

as for the CLS, have you looked at my rebuild thread? have you looked at the way yardboy's tank is setup. these are fairly different but contain a lot of the same ideas. i prefer to have inlets high and outlets low. outlets do not get clogged, so if they are down below the LR no big deal. do you have an idea on what kind of critters you want to keep in the tank? i would go with big holes like 1" or even 1.5" for the inlets and outlets. you can always put reducers on it for smaller pipe sizes, but if you ever wanted to try an insane amount of flow you will have the options.

G~

[robsee06]

Great info guys...thanks!

If I go with the 1" intake what diameter should I use for the return? I am planning to use an Iwaki 30 or 40 rlxt (1" outlet) pump. Does this mean I should use 1" PVC or am I supposed to use something smaller than the intake for the return (i.e. 3/4")?

I have a deltec AP600 that advertises 160gph throughput. I am shooting for 2-3X turnover with this sump arrangement and adding extra flow with the CLS.

Thanks

[Geoff]

you can go smaller on the outlet if you want. the only rule is you do not want to go smaller on the inlet. starving pumps is bad. when running PVC it is best to keep the diameter as large as possible untill the very last minute. this cuts down on head loss due to plumbing. i would prolly go with 1" pipe up to the tank then split it to 2 3/4" outlets.

G~

[robsee06]

OK...Cool...1" intake...3/4" return...One research fire put out!

But Wait...there's more!

Let's talk about CLS.

I have looked at many of them on the forum and I have attached a picture(s) of the one I think I like. Some questions about it.

Nobody seems concerned with ingesting a creature or two in the intakes of the CLS. It would seem this would be a real negative to the system with the volume of water that is being sucked in. Do you think the inlet cover in the picture would prevent this problem?

How many and what type of pump(s) (size and brand) would you use for this setup? Please be specific.

Based on the recommended pump what size intake and return pipe do you recommend?

Is this system adequate or do you think a spray bar would be more beneficial inplace of some of the standard returns?

Thanks again for the great advice!

[Geoff]

i am very concerned with inlet suction and velocities. so much that i am going to hind them behind a coast to coast overflow. this will distribute the suction over a much larger area. keeping the danger to critters down along with the danger of cloggs. yardboys tank is great example of this overflow idea for the CLS inlet. check out his webpage, he has a link in his signature.

spraybars are great, but they require a lot more flow than you think. if you plan on doing a spraybar, you almost need to think about 500 gph per foot of spraybar to be effective. this can go up even more if you plan on doing large holes.

G~

[robsee06]

Thanks Geoff, I checked out Yardboys setup. I hope one day to have a tank as nice as his.

You talking me out of the CLS though and here's why...

The purpose of a CLS is to generate flow, reduce heat in the aquarium by eliminating PH's, and increase aesthetics of the tank by eliminating PH's...right?

That coast to coast thing is taking up as much cubic space as a couple of powerhead although it is somewhat inconspicuous.

For my tank and 1500GPH of flow through a CLS I would need 23 linear inches on the coast to coast to meet that requirement. Double that for a slotted overflow and I basically need it to run the whole back of the tank...impractical considering I need an overflow for the sump that will take up back space also.

I'm talking myself into these Tunze Turbelle stream things. Two of them at 1600gph each should do it. They are small (4 cubic inches), can be made virtually invisible with the faux rock kit, use only 11 watts of power (1 Mag 18=145 Watts), and is only about $20.00 more than a Mag 18 itself. Add in the additional PVC, SCWD's and hole drilling for a CLS and these Tunze's are very cost effective when you go with the non adjustable models. Add a switching unit for $50.00 and BOOM... instant variable flow.

What do you think?

Has anybody used these Tunze's before that could comment on their performance...I think they are relatively new.


I really appreciate the input.

[Geoff]

decisions like yours are what i like to see around here, and are why i like it here. you have reviewed a lot of options and came up with one that works for you. Tunze are the way to go for what you are looking to do. i do not think i have heard anybody have a problem with them. they seem to be what worth what they are priced at.

G~

[Geoff]

remember to calculate the surface area of the Tunze when determining how much suction force is around them also.

G~

[robsee06]

Right On.... I couldn't agree more!

This website is perfect for unbiased views and opinion exchanging. I have learned more from you guys than the several LFS's that I have been dealing with.

I think this Tunze thing is gonna work for me...I'll let everyone know.

More questions to come!