Need advice on tuning Modular Marine Overflow

[BantyRooster97]

I have a SC 150g with a modular marine overflow box, running bean animal drain set-up. Primary at full siphon, secondary with a trickle & emergency about 1/4" higher than secondary. After I get it tuned it runs fine for a few days but as water evaporates the water level changes in my overflow box. Before my ATO kicks in it starts to make noise from the waterfall effect. I have other tanks running bean animal that don't have this problem.

Why would the level fluctuate in the overlfow box after being tuned in? My other tanks are set it & forget it.

 

[MarineandReef Jaron]

If what you are saying is correct then the water level in the sump is affecting the head pressure that your return pump is operating under which can affect the overall flow rate. I think you have a couple possible solutions.

1. Reduce the fluctuations in the water level
you could use a different ATO or possibly adjust yours. You might also be able to adjust sump baffles but we would need to see your setup.

2. Add a muffler to your seconday drain to give you a greater margin for error.
You want to adjust the overflow so that at the slowest point there is still a trickle going down the secondary drain. When the water speeds up due to natural fluctuations normally the secondary drain would get loud but the muffler will let you pass more water through the secondary drain before the sound gets noticeable. You could use a DIY durso muffler or a premade one. I like the Maggie Mufflers. https://www.marineandreef.com/ProductDetails.asp?ProductCode=ROV80100

 

[BantyRooster97]

If what you are saying is correct then the water level in the sump is affecting the head pressure that your return pump is operating under which can affect the overall flow rate. I think you have a couple possible solutions.

1. Reduce the fluctuations in the water level
you could use a different ATO or possibly adjust yours. You might also be able to adjust sump baffles but we would need to see your setup.

2. Add a muffler to your seconday drain to give you a greater margin for error.
You want to adjust the overflow so that at the slowest point there is still a trickle going down the secondary drain. When the water speeds up due to natural fluctuations normally the secondary drain would get loud but the muffler will let you pass more water through the secondary drain before the sound gets noticeable. You could use a DIY durso muffler or a premade one. I like the Maggie Mufflers. https://www.marineandreef.com/ProductDetails.asp?ProductCode=ROV80100

Thanks for the reply. So I'm using a Vectra L1 return pump. I use similar L1, M1 & S1 pumps on my other tanks & don't have this issue. Why would the level of the water in the return area affect the water level in the overflow box. This is my first tank with an external overflow box, all the other have the traditional overflow built into the inside of the tank.

 

[Eagle_Steve]

Thanks for the reply. So I'm using a Vectra L1 return pump. I use similar L1, M1 & S1 pumps on my other tanks & don't have this issue. Why would the level of the water in the return area affect the water level in the overflow box. This is my first tank with an external overflow box, all the other have the traditional overflow built into the inside of the tank.

If the water level drops too much, it can affect the pump and how much water it pushes back into the tank.

Pic of sump and knowing how much of a water drop in your return chamber occurs before the ATO will kick on is a good starting point to get this narrowed down.

For example, I had to change my ATO from an optical setup with a controller in oder to avoid this with my 180. The water level would drop about an inch or 2 before it all kicked on. This would cause my pump to change its flow based on head pressure and I would get some noise. After moving to a dual float switch setup (DIY), my water level only drops about a 1/4" before it tops off and I do not have the issue anymore.

 

[BantyRooster97]

So sump is a 40g Breeder with the modular marine baffles installed. My return area is approx 12" wide x the width of the tank (I estimate 10 - 12 gallons) @ 10" deep. My water level probably has 4"-5" of play before the ATO kicks on. I can adjust that, to much less & may give that a shot.

I have the same sump set-up (only done in glass & not as pretty) on another tank. Same levels, but running a M1. No issues.

 

[Eagle_Steve]

So sump is a 40g Breeder with the modular marine baffles installed. My return area is approx 12" wide x the width of the tank (I estimate 10 - 12 gallons) @ 10" deep. My water level probably has 4"-5" of play before the ATO kicks on. I can adjust that, to much less & may give that a shot.

I have the same sump set-up (only done in glass & not as pretty) on another tank. Same levels, but running a M1. No issues.

I would set it to be an inch of variation or less. The looking at the flow charts for the pumps, it appears the L1 is little more sensitive than an m1 at lower head pressures.

 

[BantyRooster97]

I would set it to be an inch of variation or less. The looking at the flow charts for the pumps, it appears the L1 is little more sensitive than an m1 at lower head pressures.

Thanks, I'll give that a shot. I would not have thought about that, but its an easy fix.

 

[MarineandReef Jaron]

It might help to think of a skimmer. The reason why skimmers need specific water levels is that the deeper the water level the more help the skimmer pump has pushing the water up the skimmer's neck. The natural resting point of the water is higher so the skimmer has less water to lift above gravity the higher the sump water level. This is why raising a skimmer can stop it from overflowing and lowering a skimmer will increase the bubble level in the neck.

Your return pump is doing the same thing. It is pumping at a constant setting but when the water level is higher in the sump the return pump has more help pushing water up to the tank. When the water level is lower the pump has to work harder to pump the same amount of water. This is why you only notice the noise when the water level is low and the pump is pumping less water due to the increased resistance.

 

[Eagle_Steve]

It might help to think of a skimmer. The reason why skimmers need specific water levels is that the deeper the water level the more help the skimmer pump has pushing the water up the skimmer's neck. The natural resting point of the water is higher so the skimmer has less water to lift above gravity the higher the sump water level. This is why raising a skimmer can stop it from overflowing and lowering a skimmer will increase the bubble level in the neck.

Your return pump is doing the same thing. It is pumping at a constant setting but when the water level is higher in the sump the return pump has more help pushing water up to the tank. When the water level is lower the pump has to work harder to pump the same amount of water. This is why you only notice the noise when the water level is low and the pump is pumping less water due to the increased resistance.

Perfect way to put it!!!!

 

[BantyRooster97]

It might help to think of a skimmer. The reason why skimmers need specific water levels is that the deeper the water level the more help the skimmer pump has pushing the water up the skimmer's neck. The natural resting point of the water is higher so the skimmer has less water to lift above gravity the higher the sump water level. This is why raising a skimmer can stop it from overflowing and lowering a skimmer will increase the bubble level in the neck.

Your return pump is doing the same thing. It is pumping at a constant setting but when the water level is higher in the sump the return pump has more help pushing water up to the tank. When the water level is lower the pump has to work harder to pump the same amount of water. This is why you only notice the noise when the water level is low and the pump is pumping less water due to the increased resistance.

Would increasing or lowering the speed on the pump affect / change / help this issue?

 

[billwill]

I've got this exact tank and overflow. If these other suggestions don't solve it, try playing ever so slightly with the lengths of pipes inside the overflow and/or slightly adjusting the gate valve on your drain to slightly change the level in your overflow box. Mine is dead silent.

 

[BantyRooster97]

I've got this exact tank and overflow. If these other suggestions don't solve it, try playing ever so slightly with the lengths of pipes inside the overflow and/or slightly adjusting the gate valve on your drain to slightly change the level in your overflow box. Mine is dead silent.

Thx. Mine is dead silent for a few days, then the water level changes in the overflow & I have to adjust the gate valve. It should be set it once & for get it. LOL

Luckily I have a fish room, so I can walk right up and adjust it. It just gets old.

 

[JayRozzer]

Thx. Mine is dead silent for a few days, then the water level changes in the overflow & I have to adjust the gate valve. It should be set it once & for get it. LOL

Luckily I have a fish room, so I can walk right up and adjust it. It just gets old.

You ever get this figured out?

 

[BantyRooster97]

Sorry, should have followed up. As suggested above, I changed my ATO & it has a much lower range. Now the tank stays quiet and my overflow stays about the same level all the time. Very odd that the overflow would be effected by the return section of my sump, but I guess the Vectra return pump is more sensitive to head pressure than I would have thought.