Sump Baffle Height Design Theory

Jake007 · 04/01/2010, 09:35 PM

Well I have upgrade my tank to a 120 gal and have a new used sump that someone else built. It is different than my last factory built sump so I have a couple questions and observations.

Factory Sump: after skimmer section, three baffles, first is low and the water goes over, second is high and the water goes under, third is the lowest and the water goes over.

New used sump: after skimmer section, three baffles, first is high and the water goes over, the second is the highest and the water goes under, the third is high and the water goes over.

Q. What is the significance of the height of the first baffle wall after the skimmer compartment? It seems that this sets the water height in the skimmer section of the sump? It also determines depending on the last baffle section how low your water can go and still pump (deadband for errors in topoff water). Seems that lower would be better than higher? Use ATO to keep the sump level height constant and a lower first baffle to help with an ATO water empty condition.

Q. What is the significance of the height of the third baffle setion of the sump? It seems that this height determines the amount of water in your return section. Seems that if this is lower than the first baffle with both being fairly low you would be able to pump most of your sump out with little risk of running your pump dry (largest deadband).

My new used sump has a high first and third baffle. What are the benefits of these heights? Should I modify by cutting one or both lower?

Jake007 · 04/02/2010, 06:22 PM

no sump experts?

das75 · 04/02/2010, 07:21 PM

not an expert but lots of sumps I've seen (mine included) are water flow over/under/over. Guess logic is feeding from drain and skimmer section you wouldn't be pulling the microbubbles down and though but what does is forced back up to the surface, not directly into the return pumps intake.

Jake007 · 04/02/2010, 08:44 PM

In the second picture of the new used sump. Notice that the difference between the center high baffle and the first and third baffle is about an inch. If the water level drops (evaporation) below the first baffle, the pump will be starved and run dry in less than a minute. My level stays rock solid due to my ATO unit. However, if I run out of water in my holding tank the level will start to drop.

Q. Is this baffle height normal? It seems like it needs to be lowered to allow more variance in sump water height without creating an issue for the return pump.

das75 · 04/03/2010, 01:33 AM

my center baffle is about 11/4" above the others, find with evaporation the water level only varies in the pump return compartment. If you think you need more volume in the return section, you'll need to move the baffles back and/or increase their height (or get a bigger container for your ATO).

Jake007 · 04/03/2010, 02:16 PM

Thanks for the reply. I am still not sure why the first and third baffle should be so high. The first baffle should be to force water down so the bubbles go up so it needs to have some height to it but it seems beneficial to have it somewhat lower since that will allow a greater swing in sump level without starving the pump. I wonder why the factory designed sump has the first and third lower? Do others have a different height?

JTL · 04/03/2010, 03:27 PM

The water should cascade over the first (low) baffle and under the next baffle and over the third (low) baffle. The water in the picture is too high in the second section. My middle baffle is 1" higher than the first and third. The compartment after the skimmer area is the return in my situation so if I had water that high I would need to decrease the flow from the tank.

04/01/2010, 09:35 PM	#1
Jake007 Registered Member Join Date: Feb 2008 Location: Orlando, FL Posts: 273	Sump Baffle Height Design Theory Well I have upgrade my tank to a 120 gal and have a new used sump that someone else built. It is different than my last factory built sump so I have a couple questions and observations. Factory Sump: after skimmer section, three baffles, first is low and the water goes over, second is high and the water goes under, third is the lowest and the water goes over. New used sump: after skimmer section, three baffles, first is high and the water goes over, the second is the highest and the water goes under, the third is high and the water goes over. Q. What is the significance of the height of the first baffle wall after the skimmer compartment? It seems that this sets the water height in the skimmer section of the sump? It also determines depending on the last baffle section how low your water can go and still pump (deadband for errors in topoff water). Seems that lower would be better than higher? Use ATO to keep the sump level height constant and a lower first baffle to help with an ATO water empty condition. Q. What is the significance of the height of the third baffle setion of the sump? It seems that this height determines the amount of water in your return section. Seems that if this is lower than the first baffle with both being fairly low you would be able to pump most of your sump out with little risk of running your pump dry (largest deadband). My new used sump has a high first and third baffle. What are the benefits of these heights? Should I modify by cutting one or both lower? Last edited by Jake007; 04/01/2010 at 09:41 PM.

04/02/2010, 07:21 PM	#3
das75 Registered Member Join Date: Oct 2002 Location: Edmonton AB Posts: 2,269	not an expert but lots of sumps I've seen (mine included) are water flow over/under/over. Guess logic is feeding from drain and skimmer section you wouldn't be pulling the microbubbles down and though but what does is forced back up to the surface, not directly into the return pumps intake. __________________ . Current Tank Info: 145g Starfire display (mixed reef) w/75g basement sump & 20g refugium, Barracuda return, Dart w/OM 4way CL, AI Hydras and Director.

04/03/2010, 01:33 AM	#5
das75 Registered Member Join Date: Oct 2002 Location: Edmonton AB Posts: 2,269	my center baffle is about 11/4" above the others, find with evaporation the water level only varies in the pump return compartment. If you think you need more volume in the return section, you'll need to move the baffles back and/or increase their height (or get a bigger container for your ATO). __________________ . Current Tank Info: 145g Starfire display (mixed reef) w/75g basement sump & 20g refugium, Barracuda return, Dart w/OM 4way CL, AI Hydras and Director.

04/03/2010, 03:27 PM	#7
JTL Registered Member Join Date: Jun 2003 Location: Venice Island, FL Posts: 2,532	The water should cascade over the first (low) baffle and under the next baffle and over the third (low) baffle. The water in the picture is too high in the second section. My middle baffle is 1" higher than the first and third. The compartment after the skimmer area is the return in my situation so if I had water that high I would need to decrease the flow from the tank. __________________ John 100 gallon DT and 50 gallon sump with refugium. Reefbreeders Photon V2+.

04/02/2010, 06:22 PM	#2
Jake007 Registered Member Join Date: Feb 2008 Location: Orlando, FL Posts: 273	no sump experts?

04/02/2010, 08:44 PM	#4
Jake007 Registered Member Join Date: Feb 2008 Location: Orlando, FL Posts: 273	In the second picture of the new used sump. Notice that the difference between the center high baffle and the first and third baffle is about an inch. If the water level drops (evaporation) below the first baffle, the pump will be starved and run dry in less than a minute. My level stays rock solid due to my ATO unit. However, if I run out of water in my holding tank the level will start to drop. Q. Is this baffle height normal? It seems like it needs to be lowered to allow more variance in sump water height without creating an issue for the return pump.

04/03/2010, 02:16 PM	#6
Jake007 Registered Member Join Date: Feb 2008 Location: Orlando, FL Posts: 273	Thanks for the reply. I am still not sure why the first and third baffle should be so high. The first baffle should be to force water down so the bubbles go up so it needs to have some height to it but it seems beneficial to have it somewhat lower since that will allow a greater swing in sump level without starving the pump. I wonder why the factory designed sump has the first and third lower? Do others have a different height?