[murph]

i upgraded my return pump and now the pump is overpowering the overflows. i have a super amp master 7500 comming from the basement. with the head pressure factored in, i am getting about 4000 gph. my 2 overflows in my 240 are 8" X 6" and have a 1 1/2" standpipe in each overflow. the plumbing is all 1 1/2" going into the basement to the sumps. any thoughts how i could remedy this please let me know.

murph

 

[reddhaus]

It is the divider wall that is limiting the flow or is it the actual plumbing?

 

[DLBerlin]

Read Raincheif's response here:
http://www.michiganreefers.com/forums/showthread.php?s=&postid=78035#post78035

 

[murph]

this sort of misses the point of achieving more flow. what i am trying to determine is if my overflows were made too small by the manufacturer.

 

[rainchief]

Reef Central has an overflow size/flow calculator here.

http://www.reefcentral.com/calc/drain.php

According to this, you will a 1.85" diam overflow plumming to achieve a 2000gph flow. You did say you had 2 1.5" overflows, right?

You may be at your limit. Are they hang on overflows? You could try adding a second U pipe to each if they are.

Cliff

 

[acerhigh]

this sort of misses the point of achieving more flow. what i am trying to determine is if my overflows were made too small by the manufacturer.

you never stated what they were rated at....... whether they were made too small..... probably not....... whether they are too small........ maybe for what you are trying to put through them......

sounds like you either need to increase the size of the overflows/plumbing or throttle back the pump to the max the overflows can handle.

The limits of my overflow in my 90 is the durso standpipe.... if I remove that........ the flow is greatly increased.....

JMO

Dan

 

[Sylock]

The reefcentral calculator is very conservative. I think the actual 8"x6" is your bottleneck if it is only 2 sided. You have 14" of linear overflow, RC's conservative estimate is that you need 30" with a pipe of 1.85". Because it is so conservative you will probably be ok with the 1.5" pipe, but the 14" is less than 1/2 of the 30" you need. (if I understand all the numbers correctly)

 

[rainchief]

Thanks for clearing that up. I was wondering what they ment by that. Looks like I'm going to cut some slots into my internal overflow of my new tank before I set it up.

 

[waynesreef]

Flow

You always can install a "T" to your sump on your return with an adjustable valve to balance the flow w/out slow down the pump. This way will eliminate change the existing overflow size. Just mine 0.02.

 

[Sylock]

Yeah what Wayne said, or like I'm going to do, T it to the refuge.

 

[dwall174]

what i am trying to determine is if my overflows were made too small by the manufacturer.

I don't think so! A general rule of thumb for a reef tank is at least 10 X the tanks volume turn over per hour! So in your case the manufacturer would only need to have the overflows handle 2400 GPH.

Most of us try to run a lot more than 10 X the volume & that's where we have the problems! It sounds like your plumbing could be a little too small? Here's a flow chart that shows the flow of several sizes of PVC pipe! (note the difference between the 1-1/2" & 2")

Flow Chart

1/2 " PVC
3.5 GPM
210 GPH

3/4" PVC
6 GPM
360 GPH

1" PVC
10 GPM
600 GPH

1 1/4" PVC
20 GPM
1,200 GPH

1 1/2" PVC
30 GPM
1,800 GPH

2" PVC
60 GPM
3,600 GPH

2 1/2" PVC
100 GPM
6,000 GPH

3" PVC
175 GPM
10,500 GPH

 

[murph]

great input guys i really appreciate it. i am definately going to remove the standpipes and see where that puts me. i can cover the overflows with the covers made by the tank manufacturer. i guess the next problem would be the surface area of the overflows it seems. for a reef tank i am not trying to push too much volume thru since it is a 2000 GPH flow from the pump and the tank is a 240 the overflows should handle 2400 GPH. the tank manufacturer KNEW it was a reef tank so they should have accounted for this when they made it. i am going to do some more fiddling around and see how i can get more flow down the overflows. there are a few things i am stuck with. the overflow size being the first since its built into the tank. the second being the 1.5" bulkheads in the overflows going to the sump. thanks again.

murph

 

[dwall174]

i am not trying to push too much volume thru since it is a 2000 GPH flow from the pump and the tank is a 240 the overflows should handle 2400 GPH.

I thought you stated 4000 GPH in your first post?

with the head pressure factored in, i am getting about 4000 gph.

 

[murph]

my bad , think i mistyped. i think the main problem is the durso standpipes.

 

[dwall174]

the plumbing is all 1 1/2" going into the basement to the sumps.

Do you have one or two 1-1/2" lines going to the basement?

 

[murph]

i have two 1.5" drain lines going to the basement. i have one 2" line comming up from the basement as a return line. i also removed the durso standpipes from the overflows and see very little notice in the drain efficiency. i am still stumped. i think i am just going to do what i am doing now and throttle back the return pump with the ball valve. thanks!

 

[dwall174]

Ok one last question!

When you state that the pump is overpowering the overflows, Do you mean that the water level in the tank rises to quickly! Or that the overflows don't drain fast enough?

 

[Sylock]

"Do you mean that the water level in the tank rises to quickly! Or that the overflows don’t drain fast enough?"

Aren't those two things the same thing?

 

[DLBerlin]

Not neccesarily-If the limiting factor is the slots to the overflow then the overflow will be at a normal level but the tank level will keep rising. If the limiting factor is the drain then the overflow will fill up to the top.

 

[dwall174]

Thanks DlBerlin

As you pointed out I'm just trying to narrow it down to the teeth on the overflow or drain!