Durso Standpipe Hole Size

[RDA]

Hello. Hopefully this is the right place to be posting this. I apologize if it is not.

I am finishing up my plumbing on my tank tonight/tomorrow. I have a quick question for you all.

First of all, the tank is a 100 gallon tank (60x18x21") with one corner overflow on the left hand side of the tank. 1x 3/4" return and 1x 1" drain. I am building a Durso Standpipe for the drain. I have built a 2" Durso that reduces down to 1" to go into the bulkhead. For the return I have a Mag 9.5 from an earlier project that I never ended up using. I'm going to hook that up for the time being and see how it does, to see if I need to up/downsize. I am to the point I need to drill a hole(s) into the top of the Durso's cap, but I didn't want to drill yet.

How many and what size holes should I drill for said setup? I've been reading around online and have found a ton of different answers. I trust this forum for help and advice, so I wanted to check with you all and see what was recommended. Thanks so much. I hope to have the plumbing done tomorrow so I can continue getting everything setup around the beginning of the week.

 

[Brew12]

Hello. Hopefully this is the right place to be posting this. I apologize if it is not.

I am finishing up my plumbing on my tank tonight/tomorrow. I have a quick question for you all.

First of all, the tank is a 100 gallon tank (60x18x21") with one corner overflow on the left hand side of the tank. 1x 3/4" return and 1x 1" drain. I am building a Durso Standpipe for the drain. I have built a 2" Durso that reduces down to 1" to go into the bulkhead. For the return I have a Mag 9.5 from an earlier project that I never ended up using. I'm going to hook that up for the time being and see how it does, to see if I need to up/downsize. I am to the point I need to drill a hole(s) into the top of the Durso's cap, but I didn't want to drill yet.

How many and what size holes should I drill for said setup? I've been reading around online and have found a ton of different answers. I trust this forum for help and advice, so I wanted to check with you all and see what was recommended. Thanks so much. I hope to have the plumbing done tomorrow so I can continue getting everything setup around the beginning of the week.

I think you are seeing so many different answers because there are so many different factors that come into play. My advice would be to start with a 1/4" hole and drill it in gradually increasing sizes. Another option if you really want to fine tune it instead of just getting close would be to drill a hole big enough for a plastic air line and then putting a valve on the air line and use it as a throttle. Personally, I think that would be overkill, but it is the only way I know of to keep things "perfectly tuned" as the tank ages and stuff builds up on the inside of the pipe.

Most people find that close is close enough.

 

[reefer4816]

a good option is to drill the hole big enough to fit a air tube in there. then go online or to the store and get a drip acclimation valve and put it on the airline tubing. you can then adjust how much air is let in. you ca then fine tune it

 

[RDA]

Thanks for the answers. Brew, are you saying drill up to 1/4" staring with smaller sizes and step up to 1/4"? Or start with 1/4" then work my way up gradually?

I have heard the recommendation for the airline and valve while looking around online. Would airline not be smaller than 1/4"? Would that not throttle it back too much just based off of the smaller size?

Sorry for so many questions, this is my first time setting up an overflow.

 

[Brew12]

Thanks for the answers. Brew, are you saying drill up to 1/4" staring with smaller sizes and step up to 1/4"? Or start with 1/4" then work my way up gradually?

I have heard the recommendation for the airline and valve while looking around online. Would airline not be smaller than 1/4"? Would that not throttle it back too much just based off of the smaller size?

Sorry for so many questions, this is my first time setting up an overflow.

Questions are good!

I would probably start at a 1/4" but you can always start smaller. Drilling holes in PVC is easy. There are also multiple sizes of air lines. Flow wise, you are going to approach the limit of what a single Durso drain can handle quietly so it will take a bit bigger hole. I run 2 Durso's on my 120g and have 3/8" holes drilled in both.

 

[RDA]

I can always run an inline ball valve and throttle back the return if need be. I was hoping the one drain would be able to handle the Mag 9.5, but if that's cutting it too close I can throttle back the pump. I could also sell the 9.5 or use it for something else and buy a 7 if that will be more suitable. I just had the 9.5 already so I thought I would try to use it.

 

[reefer4816]

I can always run an inline ball valve and throttle back the return if need be. I was hoping the one drain would be able to handle the Mag 9.5, but if that's cutting it too close I can throttle back the pump. I could also sell the 9.5 or use it for something else and buy a 7 if that will be more suitable. I just had the 9.5 already so I thought I would try to use it.

Rather than throttling back the pump id just add a manifold. And just dump the water your not sending to your display into the sump or to a reactor

 

[reefer4816]

Rather than throttling back the pump id just add a manifold. And just dump the water your not sending to your display into the sump or to a reactor

It'll save your pump

 

[Brew12]

Rather than throttling back the pump id just add a manifold. And just dump the water your not sending to your display into the sump or to a reactor

This +1.

I had to do it when my display was new but as it aged I found my pump flow reduced to the point I no longer bypass any flow. Always better to have too much pump than not enough and it is very easy to valve in a manifold. I built mine with a union so when it wasn't needed anymore I separated it and put on a new union that was blanked off.

 

[RDA]

Wonderful idea fellas! So id have my return pump plumbed up as usual (wide open) going back to my main tank. Maybe have the pipe y'd off with a ball valve (or similar) on the other side to only allow as much bypass as required? Or am I misunderstanding how these work?

 

[reefer4816]

Totally! And I'd use a gate valve instead of ball valve. More control. And I'd make the end of it barbed so you can put flexible hose on there to hook to a reactor or just point the hose to whatever section of your sump you want it to.

I've attached a photo of a basic manifold. This one has 4 tho. U can do as many or as little as you want. And for mine I didn't use a barb for my DT I just kept the hard plumbing going all the way to the tank

 

[RDA]

I temporarily let my return pump run tonight just to see what would happen. I have not built a manifold for the return plumbing yet (ordered the parts online tonight). So far everything seems to be running pretty decently.

Where should the water level sit on the overflow teeth when the return pump is running? Is there a certain level that is too high for comfort?

Initially I had drilled a single 1/4" hole on top of the durso drain pipe. Once I let the pump run at full power the overflow was doing the "flushing" surging level thing. I opened the hole up to 3/8" and it seems to have leveled out for the most part. Before it was doing the whole fill then flush thing. Now its running at a fairly constant level. If you stand there and watch it, it does have a slight variation in the water level inside of the overflow, but not anywhere close to what it was before. Should I open up the hole a little bit more?