Still having flow problems - plus one or two other questions

[wkopplin]

I admit I am still a little green on the whole overflow concept and I need a little advice.

I bought one of the largest CPR overflows out there from Robert along with his sump. Both are awesome and in great shape. I really like them, but I cannot seem to get the flow rate correct.

Here is a list of my questions:

1.) How much water do you have to replace a day on a 55 gallon tank with a 20 fuge and call it a 20 sump (total water volumes)? I seem to be going through a lot of water. I have checked for leaks and do not seem to have one anywhere. My tops on my tank are eggcrate and I do not have a cover on the sump, so I am sure that accounts for a lot of the evaporation.

2.) Will the depth of the overflow in the tank affect the flow rate? If so, does flow rate increase the lower or higher you go in the tank with the lip of the overflow?

3.) I still seem to be overdriving my sump with a mag 9.5 even though the overflow is rated higher gph than the pump. At least I think it is....

4.) I currently have the return flow going to the fuge and two return lines in the main tank. Would one of those scwd things be better on the returns to get more of a concentrated flow out of each side in the main tank?

Thanks for all of your help and I look forward to meeting many of you on the 13th.

Blake

[Ed]

Blake,

I lose a gallon or better a day to evaporation on my 135g (2 x 250W MH and eggcrate). How much are you losing?

If you are pumping too much water into the main tank, you can use a ball valve to slow the pump output. If too much is draining into the sump, you can use ball valves to slow the drains as well.

Hope this helps.

-Ed

[matt]

1.) How much water do you have to replace a day on a 55 gallon tank with a 20 fuge and call it a 20 sump (total water volumes)? I seem to be going through a lot of water. I have checked for leaks and do not seem to have one anywhere. My tops on my tank are eggcrate and I do not have a cover on the sump, so I am sure that accounts for a lot of the evaporation.

2.) Will the depth of the overflow in the tank affect the flow rate? If so, does flow rate increase the lower or higher you go in the tank with the lip of the overflow?

3.) I still seem to be overdriving my sump with a mag 9.5 even though the overflow is rated higher gph than the pump. At least I think it is....

4.) I currently have the return flow going to the fuge and two return lines in the main tank. Would one of those scwd things be better on the returns to get more of a concentrated flow out of each side in the main tank?

Blake

1. I evaporated 2 gallons a day on my 45. It depends on lights and amount of flow, I guess.

2. Not sure I understand the question, but my guess is that the flow into your overflow is determined entirely by your return pump flow. Raising and lowering the level of the overflow in the tank is how you regulate the water level in the tank.

3. What do you mean, overdriving the sump? Is the overflow flooding? Did you puge all the air out of the overflow? I think there's a bleed valve for this on the CPR overflow. Not sure, though

4. I can't picture what you're doing here. If you can describe the exact flow path of your water, maybe I could comment. Lot's of people like the sqwd; I never have used one.

Oh yeah, one thing I would add. I would definitely NOT use a ball valve on the drain or restrict the drain to the sump in any way. You'd be asking for a flood. Restricting the flow on your return pump, though, is fine; lot's of people do it.

Hope this helps;

Matt

[wkopplin]

Thanks Matt and Ed.

1.) I am losing about 2 gallons per day.

2.) You got my question there. I know that you control the tank level through the height of the overflow, I was just curious if that had any impact on the flow through the overflow, which I guess it doesn't.

3.) The sump keeps getting too low. The pump is driving more water than the overflow can deliver. I have a ball valve on the pump from the sump to the tank and do not have one on the drain. I agree, might cause a flood. Evaporation might be the bandit on the sump level more than the pump itself. I am rigging a top off system through the float valve in the sump. The CPR has been bled, I have a maxijet with the air line hooked to the bleed valve on the CPR.

4.) My water return line from the sump goes to a "T" intersection. One path leads to the refugium and cuts down from 3/4" pipe to 1/2" pipe. This side is the water feed to the fuge. There is a ball valve to regulate the water going to the fuge as well. The fuge drains through an open gravity drain into the sump (not quite high enough to go into the main tank). The other side stays at 3/4" pipe and leads to a second "T" with each side feeding into the main tank. I have two direct water returns to the tank feeding off this side. So, my mag 9.5 is returning water through the same line to both the refugium and the main tank. I do have a ball valve to regulate water flow from the mag drive.

[matt]

Okay, i think i understand better now. With regards to 3), if you're not leaking water and you're not overflowing the main tank, or the fuge, you must be draining the same amount of water to the sump as you're pumping out. The water level lowering in the sump must be rising in either the tank or the fuge. That's pretty clear, right? Usually, the levels will stabilize pretty quickly, but if you were to increase the flow in your return pump, what would happen is that the tank water level would rise a bit and the sump level would drop. The problem you have to watch out for is if you flood the overflow, meaning you're pumping more water into the tank than can flow out the overflow. If this happened, you'd know it right away because water would be spilling out either over the top of the overflow or the tank itself. Here's on way to check, although I'm not really familiar with the CPR overflow. Water flows over the "teeth" into a box inside the tank, then through a siphon over the edge of the tank. Look to make sure there's a noticable drop from the tank level to the level in the inside box of the overflow. When that fills up to tank level you're on your way to a flood.

BTW, gate valves are much more precise at regulating flow than ball valves; that's why they're used on skimmers.

HTH
Matt

[wkopplin]

There is a 1/4 - 1/2" difference in the level on the inside of the overflow versus the tank. I did increase the flow slightly and that increased my flow rate down the overflow, so it must be the evaporation. I can see losing that much water in a day as the top of the tank is covered with egg crate, there is no cover on the overflow or the sump and I am using egg crate again on the fuge. Have full power lights running all day on the fuge and the tank which generates a lot of heat and am moving lots of water around this system.

I have double checked everywhere for a leak and cannot find one. Tank is pretty new, no signs of wet carpet anywhere. All the pvc joints were cemented and are dry. Checked around the skimmer and sump and could not find anything wet.

I might look into a gate valve then as well.

Thanks!

[matt]

Sounds good, but if there's only a 1/4" difference between your tank height and overflow box height, that sounds dangerous to me. Again, I'm not familiar with the CPR overflows; maybe they're designed that way. Someone should know....

2 gallons/day doesn't sound excessive to me with mh lighting and an open top.

[wkopplin]

I think I had the ball valve closed too much on the return line. When I opened it up a little more, the level on the inside of the CPR went lower and the flow rate out of it went way up. I was being too cautious with the return flow rate coupled with the evaporation. That seems to have fixed it. I am waiting on a part to hook up a 7 gallon water storage container to the float valve in the sump so it will feed new water into the tank to compensate for the evaporation.

Thanks for all of your help.

[::pete::]

wkopplin can you post some pics?

[Instar]

In regard to evaporation, it will depend on outside humidy, your A/C vs heat in the house and the % your house breathes. A couple weeks ago when the humidy dropped with a front that went thru here, I went thru 5 gallons of RO on my 125. My evaporation varies between 1 to 2 gallons per day normally at 79 to 82 degrees tank temp.

[wkopplin]

Pete, I have some pics in the members gallery, but nothing of the filter system. The pics are on Page 3 of the gallery.

I also do not have my canopy installed yet, which will reduce the evaporation a little. I fabricated a cover for the sump and the external part of the overflow which should help as well.