water level at glass center brace

[zafirablanca]

I have a Nature's View 125 gallon glass tank. The tank has a glass reinforcing brace across the top of the tank at the center. I think that this is a fairly common design. So here is my question:
I am trying to decide the right flow rate to keep my return pump set at, I have a ball valve installed after the pump to control the flow. I have 2 Marineland Tidepool SOS external overflow boxes (rated up to 600 gph each) going to a 20 gallon tall sump and a 30 gallon refugium. I would like to try and operate the pump with the ball valve as wide open as I can, to reduce back pressure on the pump and reduce the amount of powerheads in the tank. Pump is rated for 900 gph.
I plumbed the return to the two back corners of the tank, and each pipe outlet splits in two, kind of like a vertical spraybar. One outlet points diagonally across the top of the tank toward the center and the lower one points toward the front glass (same design on the other side of the tank).
Well, as I open the ball valve to increase the flow, the water level rises in the tank. The overflows continue to work, but the water level in the tank just gets a little higher as I open the valve a little more. I am at the point where the water is touching the glass center brace (with the valve almost 1/2 closed). Is this normal? I worry that I am playing with fire by keeping such a high water level in the tank. But honestly, I dont really know if the water level is just supposed to be that high. If I could lower the height of the overflow boxes, I would, but they are not adjustable like that. I am also concerned that my overflows are not keeping up as well as the claim to (2 x 600 gph?).
Any advice from those with experience with this tank design would be extremely comforting to me at this point.
Thank you!
-Christine

 

[broomer5]

Christine,
Do you have the installation instructions for the Tidepool SOS ?
Step 18
Figure 18a and 18b
Describes adjusting the "overflow control rod" either up or down, to adjust the water level in the tank as compared to water level in the overflow.
Did you try this already ?

 

[zafirablanca]

Broomer,
Yes, I have moved the control rods around to see what happens. Basically I have them extended all the way up/ maximum capacity flow now. Anything less than that drops the water level below the recommended level mark in the overflow box and causes great air sucking noises. I 'feel' that this means that I am at or approaching max flow through the overflows. What do you think?
Do you think that the water level is supposed to be this high in the tank?
Thanks,
-Christine

 

[zafirablanca]

Yeah, I think that my pump is alot more powerful than I expected. I can't say enough about how quiet and efficient this Dolphin pump is. Anyway...........
Does the water touch the glass cross brace on anyone's (or everyones's) tank?
Can my tank run too full????
Thanks for the replies.
-Christine

 

[jester]

I wouldn't risk that height for normal operation. I let mine get that high only when I lose syphon and there is no more water in the sump to pump into the tank. I've done this only to test power outage and overflow failure. I marked 2 lines in the sump, MAX ON, and MAX OFF for waterfill levels. I would suggest bigger overflows.

 

[zafirablanca]

Thanks Jester,
Are there bigger overflows? I have 2 already. Should I get a third?
I am wondering at this point if it is a little moot if I add another over flow to avoid putting more equipment in the tank (in the form of powerheads).
So , it seems that this is a little to high a water level for normal operation? Right? Anyone else with input/ opinions on this?
Thanks again,
-Christine

 

[jester]

Replace one that you have. What size is the bulkhead and the diameter of the j tube?
Yes there are larger. I have one rated for 1400gph and one for 700 gph on my tank.
The 1400 has dual 1" bulkheads, and the other has 1 1"bulkhead.

 

[zafirablanca]

Jester,
May I ask what brand overflow boxes you use? I have no problems at all with the Marineland SOS boxes like I have heard about from others who have other brands. Just need more flow. I see Lifereef and CPR make larger models. Any suggestions?
Thanks!
-Christine

 

[zafirablanca]

Oh, sorry I didn't answer the question. I have two seperate overflows, each with a 1 1/4 " diameter drain hose. They are supposed to be rated up to 600 gph, and my pump rated up to 900 gph w/no head pressure. Go figure.

 

[jester]

I use the CPR's. I looked up the SOS's, and think that the u bend on the top of the box might be a little small. I's hard to see from the pictures on the web though.
can you get me a pic of your plumbing and sump? Is it a straight vertical shot down into the sump, or do you run the tubes at a higher angle? Do you have any 90 degree bends? Is the drain hose corrugated on the inside? Oh, how high is the water level in relation to the bottom of the box teeth inside the tank?

 

[reefsoe]

One of the reasons for this is because the grooves in the overflow box are not deep enough... this can easily be corrected with a dremmel but makin a few of them deeper on the box thw water lvl will be better and the surface wont be raised in the middle.

 

[zafirablanca]

Jester,
The 'U' tube on the SOS is not exactly a 'U'. It is nearly the same, except it is flattened out so that it is wider than tall and somewhat box shaped. Same idea though.
I have a roll of film that I am using up right now for pics, sorry no digital yet!
I have the boxes set up on either side of the tank in back. My sump is on the right side of my cabinet, fuge on left, on its own stand - to gravity feed to the sump. The drain hose is corrugated on the outside, smooth on the inside, 1 1/4 ", what came with the SOS.
The overflow on the right flows straight down into the sump, no turns or angles.
The overflow on the left does travel at an almost horizontal position for a bit (which at that point it tees off to feed the fuge) then down to the sump. Believe it or not, that works really well. The tee doesn't at all restrict the flow, I think it may even increase it.
The water level in the tank appears to be between 1/2" to 3/4" above the bottom of the overflow box teeth.
Did I get it all? I hope this helps, thanks again.
Reefsoe,
Do you think that the dremel thing would work? I think that we have one. Hhmmmmm.... Oh and the water level is not actually higher in the center, it just reaches the glass brace that is across the top of the tank at the center. The level is basically at the where the glass meets the plastic rim around the top edge of the tank. Pretty high.
Thanks again for all of the input! It is really soo much appreciated.
-Christine

 

[broomer5]

I run my tanks so the tankwater level is "just at" the point where the glass/plastic rim appear to meet.
As long as the tank's not overflowing the rim - and you have an inch or so of room left in the tank - I don't see a problem.