pump/flow question

[jkienzpac]

http://reefcentral.com/gallery/data/500/207100IMG_0802.jpg

I finally got my new oceanic 215RR flat on my stand and level and I'm almost ready to start my plumbing. I have a 90 g acrylic sump for under the stand and I'm researching external pumps. Looking at the reeflow dart. I have 6' of head so flow rate is estimated at 2400 gpr. I'll probably divert some flow back to sump and use additional powerheads in the tank. The tank is pre- drilled with 2 overflows. The drain pipes are 1" and the return are 3/4". The pump is 2" in and 1.5" out.
my question is
1. will my 2x 1" drains and 2x3/4" returns handle this flow rate without too much turbulence? I've heard of some people using both drain and returns from the overflow as a drain and plumbing separate returns up behind the tank.
2. any feedback on this pump and size for my tank would be great.

Thanks,

Jeff

[uncleof6]

I really should add a line to my signature: Reef Ready tanks-- aren't. Chuckles. Anyway, I am going to throw some thoughts out there.

Vertical head will be from the waterline in the return section of your sump, to the return line outlet, so I think there will be a bit less than 6' vertical head. (just looking at it.) The friction loss from splitting to 2 -3/4" returns will jump it up considerably. So you looking at running a return line up over the top is a good plan. 1.5" all the way. Do you need 2 returns in the tank? I don't really think so. Powerheads-- used well, will mix things up enough.

1) 2 - 1" drains, if using durso modified standpipes, will not handle this flow rate without considerable "turbulence" read noise and bubble trouble, and instability. Even with 1.25 or 1.5" dursos, you will have pretty much the same problem. Even with a 1.5" bulkhead in the bottom, this would still be a problem. So for the main drains, I am thinking (dangerous but not uncommon) my standard 1.25" full siphons on 1" bulkheads.... range 1200 + gph per. I just hate 3/4" bulkheads, for return or drains. So I ain't sure what size pipe you would need to equal the flow through the siphons, for emergency back up other than big.... (personally if the bottom ain't tempered I would open them up to accept a 1" bulkhead...) thinking 1.5" would work, but I am not doing the math. That's bean's dept. Better would be to to pull the overflows out, drill the back of the tank, plug the existing holes, mount an internal coast to coast, and plumb three 1.5" drains, full siphon, open channel, and emergency-- oh that is bean's dept also.

2) I use darts, and for this size range of tanks, it is great. (without diverting flow back to the sump, unless to feed a "fuge".

OK, I'm done......

Jim

[jkienzpac]

Jim,

i'm very reluctant to drill the bottom of the tank or the back (no real experience with this) and not a big fan of siphons. What if I used both 3/4 " returns for drains along with the 2 1" returns and run a 1.5" return over the top. Is there a way to calculate the max flow rate with this set up? I can always reduce pump flow by diverting some return back to the sump.
based on the calculator 2400gph needs about 2" drain. 1500 about 1.6" drain.
Not sure how to calculate flow rate of two 1" and two 3/4" drains combined. I know it's not additive.

i'm willing to decrease my flow to 1500 gph or less if needed. Would it be better to use the dart and divert water or go to the next smaller pump.

Also is there a recommended fow rate for the sump. The flow of my fuge can be independently controlled and will free flow back to the sump return.

Thanks,

Jeff

[uncleof6]

Let's ignore the physics of durso modified standpipes for a moment, and look at pipe size. (And use the calculator numbers.) As far as area, 2 - 1" and 2 - 3/4" standpipes will have a combined area of 2.45 sq. in. a 2" pipe will be 3.14 sq. in. and a 1.5" = 1.77 sq. in. so in calculator terms, flow would be between 1500 and 2400 gph.

But when you consider how durso (and similar modified standpipes) actually function (the physics of them) You may get ~100 gph through a 1" and less through a 3/4" without instability, noise, and bubble trouble. For a 1.25 durso, on 1" bulkhead.... the flow goes up a bit, but with reported problems in the 320 gph range, and on the 3/4" bulkhead this number will be lower. The only way to solve the problems with these types of standpipes is to slow the flow down to the point where the flow would be insufficient for your tank. I look at 400 gph through a 1.5" durso on a 1.5" bulkhead. And some that mess with this stuff, put it at 320 in a 1.5". Just as a bit of trivia, the "inventor" of the durso modification states that a 1" durso standpipe does not work, and suggests the smallest practical size is 1.25" on a 1" bulkhead.

So going with your proposed setup, using a Dart would be a waste of a good pump. And a smaller pump would be better suited to the drain capacities. Why waste the electricity to dump the water back in the sump, when where you want it is in the tank.

Flow rates have some controversy associated with them, but 5x the system volume is archaic and predates "reef" type systems, and I am talking about the sump return-- not total circulation. Matching the flow through the sump to the flow rate of the skimmer-- to improve skimmer efficiency, is a myth. For sump return, I use 10x total system volume, and for total circulation, 40 - 60x. Some suggest as high as 100x.

So saying the Dart is a good pump for you size system, is accurate. But given the limitations of the holes in the tank, it is not. Some will say, since "your" skimmer only flows 300 gph, that sump flow over 300gph is a waste, but even using the archaic 5x, this is obviously inadequate.

I don't know why you are uncomfortable with full siphons, but I understand being uncomfortable with drilling tanks, every one is a bit uneasy with it. At any rate, I am just giving you food for thought.

Jim

[JTL]

What do you recommend for a return pump at 1000-1200 gph and 5' of vertical head pressure? True Wye and two 1" returns, each with a 90 as they enter the tank.

[jkienzpac]

Jim,

thanks for the feed back. I've never used these types of standpipes but was afraid they might be limited. It sounds like I may need to use an overflow box like you said. I've been out of the hobby for 10+ years and at that time had trouble with frequent siphon breaks in past. That is my only real concern with using them.
Could an external overflow be used in conjunction with my current setup?
Also what did you mean by emergency back up in your first response?

Jeff

[arredondojason]

RC has a calculator that will tell you your final flow to your tank after your plumbing and you can put in the type of pump you are using to so you can see what different pumps will do.
here is the link.
http://www.reefcentral.com/calc/hlc2.php

here is a drain/overflow calculator to.
http://www.reefcentral.com/calc/drain.php

also i agree with you about using a ball valve to devert it back to your sump i did this with my 240 gallon tank and you can adjust the flow to what you want it to be and use powerheads in your tank for more movement.
i hope this info helps you out.

[uncleof6]

<a href=showthread.php?s=&postid=15643800#post15643800 target=_blank>Originally posted</a> by jkienzpac
Jim,

thanks for the feed back. I've never used these types of standpipes but was afraid they might be limited. It sounds like I may need to use an overflow box like you said. I've been out of the hobby for 10+ years and at that time had trouble with frequent siphon breaks in past. That is my only real concern with using them.
Could an external overflow be used in conjunction with my current setup?
Also what did you mean by emergency back up in your first response?

Jeff

The emergency backup for a full siphon, is a separate standpipe, normally dry, and if the full siphon for whatever reason blocks up, the emergency will take the flow, rather than overflowing the tank.

This is a long read, granted, but you can pick up the basics within the first couple of pages, concerning full siphons and internal/external overflows. With this type of design, you are not going to have siphon breaks, and if the power goes out, it will restart.

http://reefcentral.com/forums/showthread.php?threadid=1310585&perpage=25&pagenumber=1

In the past ten years, I have not really seen any major innovations in reefkeeping, just rehashes of things that have been around for a lot longer. Notable things since the Jaubert plenum/dsb combination in the early 90's have been T5 lighting, the potential of LED lighting (if plasma caters to the spectrum-- LED will die) and propeller pumps such as the vortech. Oh-- ok bean, your drain system is innovative also.

Jim

[jkienzpac]

Jim ,

Finally got a chance to read through the thread you recommended(the first several pages anyway, things got a bit messy thereafter) and I now know what you mean by full siphon standpipe. I thought you were referring to those old fashion overflows that required priming. anyway, as I said the tank came with the dorso like standpipe with a 1" drain and 3/4" return in each of the two overflows. Well, I measured the tank "holes" and they are all 1 3/4 " diameter. So the two 3/4" returns could accept a 1" bulkhead.
Therefore it seems like I could, in each overflow, have a 1.25" full siphon through a 1" bulkhead and a 1'' emergency overflow drain as well. Based on beans calc, sound like this could handle the flow rate and be nice and quiet. What do you think?

Thanks,

Jeff

[sjm817]

I'm not a high sump flow type of guy. A reasonable about of flow will work just fine with the normal Durso type standpipes and return plumbing. Using a too big pump and then diverting flow back to the sump is a waste of electricity. Use the right size pump and throttle it back a little if needed. That tank is highly likely to have a tempered bottom. Tying to drill it will destroy the tank.

Hard to tell from the pic. What types of overflows? Corner or back wall? If you want to do a full siphon overflow with that tank, you can do a "Herbie" overflow.
http://www.reefcentral.com/forums/showthread.php?s=&threadid=344892

Nice looking tank and stand setup BTW! :thumbsup: