Overflow Not Draining at a Tee Equally

EvanStagnaro · Mar 17, 2021

Hello everyone!

I'm sorta new to the hobby, or specifically, I'm new to the part of the hobby in having a sump. I've had tanks with hang on the back equipment for years, but decided to upgrade to a 150 gallon tank with a sump. I've set up and plumbed my tank, and finally got it all aquascaped and filled with water (after two days of RO/DI water making) this evening. Upon turning on my return pump (a Neptune Cor-20) I was very pleased to see that it was all plumbed properly and there were no leaks. Though I did notice that I am having some flow problems as I have flow meters on two of my three pipes where my overflow splits off. I've essentially split my overflow into three main pathways. One of those pipes goes to a rollermat, which is the main area of flow which has about 500 gallons per hours running in it (or will have about that much). This is a 1" pipe going to the rollermat which leads into the skimmer, etc. This pipe has a 1 inch flow sensor attached to it, and I am getting good flow. through this pipe, as expected. The second direction is over to the refugium, where the flow will be much lower, so I used a 3/4 inch pipe, then stepped down to 1/2 inch to use another flow sensor. Both of these directions have a gate valve to adjust and fine tune the water being distributed into each section of the sump. Finally, I added a third option. for the water to travel, which I intended on being an "in-drain emergency" for times I need to shut off the rollermat flow or lower for some reason without having to turn off my return. This was so that my return would not run dry and there would still be a place for the water to go if it cannot go one of the other two ways. I plumbed this at a different level, meaning I purposely faced the tee up, making the water have to go against gravity, which in my mind would have made this the last direction it would want to go, but for some reason, I am getting great flow to the rollermat/skimmer/etc, but no flow at all to the refugium, and instead the water is traveling against gravity to the "emergency." I've attached a diagram below of my overflow drain setup. My thought is that potentially, the "emergency"/last resort is creating a syphon and sucking the water from the pipe up against gravity and taking all the water that should be flowing to the refugium. I can drill a hole in the top of the peak on the "emergency", which would break the syphon if that is the case, but I am not sure. Does anyone have any ideas, or have any thoughts as to how I can get flow to my refugium, instead of the "emergency" direction? Ideally without having to replumb the tank. Thank you so much in advance!

nudave · Mar 17, 2021

I suppose the first question I have is - the horizontal pipe coming from the main drain line, is that level? I thinking the T off the main drain isn't and the water has to travel uphill even slightly, will result in the filling of the return chamber 3/4" drain.

attiland · Mar 17, 2021

EvanStagnaro said:
Hello everyone!

I'm sorta new to the hobby, or specifically, I'm new to the part of the hobby in having a sump. I've had tanks with hang on the back equipment for years, but decided to upgrade to a 150 gallon tank with a sump. I've set up and plumbed my tank, and finally got it all aquascaped and filled with water (after two days of RO/DI water making) this evening. Upon turning on my return pump (a Neptune Cor-20) I was very pleased to see that it was all plumbed properly and there were no leaks. Though I did notice that I am having some flow problems as I have flow meters on two of my three pipes where my overflow splits off. I've essentially split my overflow into three main pathways. One of those pipes goes to a rollermat, which is the main area of flow which has about 500 gallons per hours running in it (or will have about that much). This is a 1" pipe going to the rollermat which leads into the skimmer, etc. This pipe has a 1 inch flow sensor attached to it, and I am getting good flow. through this pipe, as expected. The second direction is over to the refugium, where the flow will be much lower, so I used a 3/4 inch pipe, then stepped down to 1/2 inch to use another flow sensor. Both of these directions have a gate valve to adjust and fine tune the water being distributed into each section of the sump. Finally, I added a third option. for the water to travel, which I intended on being an "in-drain emergency" for times I need to shut off the rollermat flow or lower for some reason without having to turn off my return. This was so that my return would not run dry and there would still be a place for the water to go if it cannot go one of the other two ways. I plumbed this at a different level, meaning I purposely faced the tee up, making the water have to go against gravity, which in my mind would have made this the last direction it would want to go, but for some reason, I am getting great flow to the rollermat/skimmer/etc, but no flow at all to the refugium, and instead the water is traveling against gravity to the "emergency." I've attached a diagram below of my overflow drain setup. My thought is that potentially, the "emergency"/last resort is creating a syphon and sucking the water from the pipe up against gravity and taking all the water that should be flowing to the refugium. I can drill a hole in the top of the peak on the "emergency", which would break the syphon if that is the case, but I am not sure. Does anyone have any ideas, or have any thoughts as to how I can get flow to my refugium, instead of the "emergency" direction? Ideally without having to replumb the tank. Thank you so much in advance!

First the pie to the return chamber line is not against gravity once primed as the pipe’s end is low and what matters is where the water starts and where exists from it. The turns have slowing effects but that is little

The other thing is that on the refugium end you go down 1/2’’ pipes for the flow sensor. To allow more flow that way you should use 3/4’’ up till the last T. That would enable more flow that direction leaving the return chamber less pressure. The other thing you could do is restrict the flow with a 1/2’’ end on the return chamber line. That would make the pressure more equal but possible would not be enough.

with this pipeline you will always have flow on the RC end.

The easiest would be to put a gate valve at the end of RC line so you have a manual way of enabling that route when required.

my other idea is is to put an airline /pipe going above the DT water level from the top loop of RC line. This would break the priming therefore the flow likely would stop and would require high pressure to restart. This would need to be tested though to know how big that airline / pipe would need to be to make it work.

hope this helps

vetteguy53081 · Mar 17, 2021

If you had a shutoff or ball valve, you could reduce flow slightly to equalize it

EvanStagnaro · Mar 18, 2021

attiland said:
First the pie to the return chamber line is not against gravity once primed as the pipe’s end is low and what matters is where the water starts and where exists from it. The turns have slowing effects but that is little

The other thing is that on the refugium end you go down 1/2’’ pipes for the flow sensor. To allow more flow that way you should use 3/4’’ up till the last T. That would enable more flow that direction leaving the return chamber less pressure. The other thing you could do is restrict the flow with a 1/2’’ end on the return chamber line. That would make the pressure more equal but possible would not be enough.

with this pipeline you will always have flow on the RC end.

The easiest would be to put a gate valve at the end of RC line so you have a manual way of enabling that route when required.

my other idea is is to put an airline /pipe going above the DT water level from the top loop of RC line. This would break the priming therefore the flow likely would stop and would require high pressure to restart. This would need to be tested though to know how big that airline / pipe would need to be to make it work.

hope this helps

Thank you! I'll most likely end up putting a valve on the end of the RC line. Thank you for your response! I appreciate the help!