Float cutoff switch for return pump...?

[Potatohead]

Hi everyone, first post here.

I have been doing so much research over the past few days my brain is hurting. I want to set up a 36g reef tank. I'm going to run a 10g sump since that is all I can fit in the stand.

I am going to run an eshopps pf300 hob overflow. I have thought about drilling over and over but it just doesn't make sense to me in this application, if I did it I would want a beananimal setup and the overflow box just gets way too big for this small tank.

Now for extra protection I was thinking about running a float level sensor to turn the pump off if the overflow ever stops functioning. I'm wondering if I have to run an actual auto top off system, or if there is another way to do this. If you just run a float sensor it will stop the pump, but then of course you will have drain from the lines and the top portion of the tank and it will turn back on. Are there any methods around this?

Also, should I even worry about it since my sump will only have six or seven gallons in it? It would overflow maybe four gallons which isn't lots... but of course it would kill the pump if I'm not around.

Thanks

 

[JammyBirch]

Here's what i'm reading, correct me if i'm wrong... You're going to run a single drain line, because you don't want to drill the tank. Since you'll only be using one drain line you're concerned with a malfunction and would like to shut the return pump off in order to stop an overflow.

Correct...?

If so there is an entire post about this in this forum.

Search "emergency drain a must have"...

The short story version is this...if you are truly concerned about a blockage event then you should seriously consider an emergency drain, meaning drill it. If that is something that you are absolutely against then you need to make sure your sump can handle two things

(1) The added volume of water that is above the drain pipe in the DT, the volume of the drain pipe itself and about 20% of that number as a safety factor, in case of a power outage.

(2) The return chamber needs to be small enough so that if the drain were blocked the return pump cannot pump enough water in the display tank to overflow it.

There are two events that can cause overflows, (1) power outage where all of the above mentioned water ends up in your sump and (2) drain blockage where all of the water in your return chamber ends up in your Tank.

Your ATO will need to be an integrated controller type like the Tunze Osmolator or the SMART ATO. These ATO's have built in alarms that will not allow them to continue to pump top off water into your sump if your drain is blocked.

This post may open up a can of worms but this is how i have been running my system for years with no issues.

 

[Bent]

He has a HOB overflow and is worried about the siphon breaking, which is a legitimate concern. In my experience with those, it's not a matter of if, but when.

My suggestion is to drill it. It's not hard to do and the piece of mind is worth it. You don't have to do a bean, you can do a herbie and be just fine.

But if your dead set on a HOB, if you don't already have one, CPR makes one that utilizes an aqualifter that will restart the siphon should it break. If you already have one you can buy an aqualifter, run the tubing into the U tube from the drain box side and mount it somewhere. I would use that in conjunction with your float switch. I think having both redundancies would really alleviate most concerns I had.

But...by the time you get done paying for all of that, you could have bought a reefsavvy or modular marine overflow and have it done correctly and really give you piece of mind.

Again though, if your dead set on using a HOB, about the only two safety nets you can set up is a self priming pump like an aqualifter stuck into the U tube of the overflow that will keep the siphon going and a float switch that will kill the return pump should the water level in the display start rising should the siphon break and the priming pump fail.

Good luck.

 

[Potatohead]

Here's what i'm reading, correct me if i'm wrong... You're going to run a single drain line, because you don't want to drill the tank. Since you'll only be using one drain line you're concerned with a malfunction and would like to shut the return pump off in order to stop an overflow.

Correct...?

If so there is an entire post about this in this forum.

Search "emergency drain a must have"...

The short story version is this...if you are truly concerned about a blockage event then you should seriously consider an emergency drain, meaning drill it. If that is something that you are absolutely against then you need to make sure your sump can handle two things

(1) The added volume of water that is above the drain pipe in the DT, the volume of the drain pipe itself and about 20% of that number as a safety factor, in case of a power outage.

(2) The return chamber needs to be small enough so that if the drain were blocked the return pump cannot pump enough water in the display tank to overflow it.

There are two events that can cause overflows, (1) power outage where all of the above mentioned water ends up in your sump and (2) drain blockage where all of the water in your return chamber ends up in your Tank.

Your ATO will need to be an integrated controller type like the Tunze Osmolator or the SMART ATO. These ATO's have built in alarms that will not allow them to continue to pump top off water into your sump if your drain is blocked.

This post may open up a can of worms but this is how i have been running my system for years with no issues.

I was thinking about drilling an emergency line into the overflow box itself, and that would help if the drain line clogged. It wouldn't help if the siphon on the box itself broke.

I guess I can build the sump so that the return chamber is small enough it won't overflow, but if that happened it would still kill the pump.

He has a HOB overflow and is worried about the siphon breaking, which is a legitimate concern. In my experience with those, it's not a matter of if, but when.

My suggestion is to drill it. It's not hard to do and the piece of mind is worth it. You don't have to do a bean, you can do a herbie and be just fine.

But if your dead set on a HOB, if you don't already have one, CPR makes one that utilizes an aqualifter that will restart the siphon should it break. If you already have one you can buy an aqualifter, run the tubing into the U tube from the drain box side and mount it somewhere. I would use that in conjunction with your float switch. I think having both redundancies would really alleviate most concerns I had.

But...by the time you get done paying for all of that, you could have bought a reefsavvy or modular marine overflow and have it done correctly and really give you piece of mind.

Again though, if your dead set on using a HOB, about the only two safety nets you can set up is a self priming pump like an aqualifter stuck into the U tube of the overflow that will keep the siphon going and a float switch that will kill the return pump should the water level in the display start rising should the siphon break and the priming pump fail.

Good luck.

I'm not dead set on it, in fact I'd rather drill it. It's simply cheaper, easier, faster to run an hob but that's probably being lazy. I also don't really want to take up much room in the tank. What is the smallest overflow I could use? From what I understand with a Herbie you need about 6" of water level above the drain to be able to re-start the siphon after a power outage. With a 3/4" PVC elbow also back there that seems like it would be a pretty large overflow box. If I only needed like 1 - 2" of water height above the drain I could do it pretty easily, but from what I understand that doesn't work well to re-start the siphon.

 

[fishgate]

A correctly designed sump will not flood if the pump stops or the siphon stops (+1 to JammyBirch). Just do that. HOB overflows work fine. I used an eshopps for years with no issues at all.

 

[Potatohead]

I think I can make it not flood, if I design the return chamber small enough, which makes perfect sense. I could add the float switch to turn off the pump at that point but I wouldn't be able to put the return pipe under water in the tank (to prevent a siphon) but I don't think I want that noise so I might just risk the pump I guess, it's not super expensive anyway. I'll figure it out with some fiddling.

 

[CStrickland]

I'm not dead set on it, in fact I'd rather drill it. It's simply cheaper, easier, faster to run an hob but that's probably being lazy. I also don't really want to take up much room in the tank. What is the smallest overflow I could use? From what I understand with a Herbie you need about 6" of water level above the drain to be able to re-start the siphon after a power outage. With a 3/4" PVC elbow also back there that seems like it would be a pretty large overflow box. If I only needed like 1 - 2" of water height above the drain I could do it pretty easily, but from what I understand that doesn't work well to re-start the siphon.

I think something like this ghost overflow will take up less space in the tank than an eshopps. http://reefsavvy.com/the-reef-savvy-difference/ there's several DIY versions out there too. Since you can't really go back and drill the tank once it's stocked, it might be better to just bite the bullet.

If you do go with the hob, I'm not a fan of the aqualifter style. The eshopps design is very good and if it is set up properly it's hard to break the siphon in a way that the pump helps with. Like, if you have enough flow to push the bubbles through and all, then your flood-risk is coming from a physical obstruction like a snail, which the pump won't resolve. I don't think the pump adds much reliability, but drilling into the u-tube for the pump line adds a siphon failure-point.

you can put your return under water as long as you put a hole in it just below the waterline to suck air and break siphon if it starts to drain the tank

 

[Potatohead]

I think I am going to do the Eshopps HOB unit for a number of reasons. The only downside is a siphon break, which is likely a rare event, and I can set up the sump to not flood the tank. I am also very diligent with maintenance and I don't foresee any issues checking on it daily, I need to feed the fish at some point anyway of course. I even thought about running two of them but I would imagine most scenarios that would break siphon of an overflow on one side would also break the siphon of one on the other side, short of one of them actually failing mechanically. That would also slow the flow a lot through them which I hear is bad.

 

[fishgate]

I think I can make it not flood, if I design the return chamber small enough, which makes perfect sense. I could add the float switch to turn off the pump at that point but I wouldn't be able to put the return pipe under water in the tank (to prevent a siphon) but I don't think I want that noise so I might just risk the pump I guess, it's not super expensive anyway. I'll figure it out with some fiddling.

Running out of water in the return chamber isn't as dire as you think. For one, there will always be enough water in it to keep the impeller with some water splashing around it. As long as you get to it within a day of running "dry" the pump will survive. An auto-shutoff for the pump in this scenario is a good idea however. The more likely scenario is you forget to fill the ATO reservoir and it runs out of water from evaporation.