External overflow box issues

[NanCrab]

Ok so we sold all of our large tanks and we’re going to get out of the hobby due to my continued serious health issues but really still wanted something. We decided to convert on of our non-copper QT tanks (a 49g breeder) into a reef tank. Everything is going pretty good EXCEPT this is our first time using an external overflow box and we keep having issues with it suddenly not working properly. Either the water won’t drain fast enough and the tank water level gets super high and the sump gets so low air bubble are getting shot into the tank or the pump isn’t working properly and the water level in the tank suddenly drops and the sump fills to the point of almost overflowing. I desperately need a siphon break. I know that @Adam taught us how to add one with a John Guest fitting on our drilled tank, but not sure if that will work on the clear U tube or not. We need to do something ASAP before the real disaster happens that we aren’t home to address. Luckily each time there’s been a problem we’ve been able to avert disaster, but just barely.
Any words of wisdom would be appreciated

 

[ichthyoid]

Sounds like your pump isn’t consistent?

Fwiw, I ran a siphon overflow years ago, but would never trust one again.

The best solution-
I would drill the tank & install something like an Eshopps overflow kit with built in durso & a Hayward gate valve to adjust it.

 

[NanCrab]

Sounds like your pump isn’t consistent?

Fwiw, I ran a siphon overflow years ago, but would never trust one again.

The best solution-
I would drill the tank & install something like an Eshopps overflow kit with built in durso & a Hayward gate valve to adjust it.

Would I have to empty and dismantle the entire tank to do this? I feel like the pump is too large for the system. I do have a slightly smaller one I can swap out but my husband has been resistant to doing it.

 

[ichthyoid]

If your current pump volume is so great that it exceeds the flow capacity of the siphon overflow, then you could either -

-replace the pump, with a smaller one

-restrict the pump, such as using a valve on the discharge side. This does create some added back pressure & possible added wear due to increased thrust load.

-or, make a variable bypass for the pump by using 2 T’s & a valve connected to both the suction & discharge of the pump. This will allow you infinite control of the pump output.

 

[ichthyoid]

Would I have to empty and dismantle the entire tank to do this? I feel like the pump is too large for the system. I do have a slightly smaller one I can swap out but my husband has been resistant to doing it.

Drilling a tank typically requires that it be empty.

 

[joeyprice]

Does it need to be controlled on both the uptake and discharge? Couldn't you just put a ball valve in the return and a T that returns to the sump right before it?

 

[sharis100]

Does your overflow have a place to use an aqualifter pump to keep the siphon going and restart if power interruption to prevent that from occurring?
My overflow on the temporary pest tank uses an aqualifter to maintain siphon. No issues stopping at all unless I let the overflow get dirty. Only maintenance is cleaning occasionally and changing out air tubing if it gets clogged- which has only happened once in last 1.5 years and siphon still held. So no tank issues.

 

[bg2311]

Does your overflow box have 1 or 2 drain pipes? Our display has a CPR HOB overflow with one of the small Aqualifter pumps (front of photo) to maintain the siphon.

 

[bg2311]

View attachment 42487

Does your overflow box have 1 or 2 drain pipes? Our display has a CPR HOB overflow with one of the small Aqualifter pumps (front of photo) to maintain the siphon.

When there's an issue with the water level, it's usually either something clogging the lifter pump that helps maintain the siphon on the overflow box, or the filter mesh in the sump before the return pump is clogged and needs cleaning.

 

[samsisson]

I switched from an HOB with the U-tubes to one of the CPR aquatics that uses an aqua lifter due to similar siphon problems. What happened for me was that bubbles from the water in the tank spilling through the teeth would get into the tubes, eventually causing a break in siphon. Mine had two tubes so it never got to the point where it caused an overflow, but it did scared me enough to spend the coin on a CPR instead

 

[ichthyoid]

Does it need to be controlled on both the uptake and discharge? Couldn't you just put a ball valve in the return and a T that returns to the sump right before it?

Yes, to the 2nd question. The bypass can go to the suction side of the pump, or sump. Whichever is closest and/or easiest.

As to the 1st question, flow isn’t “controlled on both uptake & discharge”. Only the pump discharge. The example was to tie that bypass to the suction side, as a loop.

 

[NanCrab]

Does your overflow have a place to use an aqualifter pump to keep the siphon going and restart if power interruption to prevent that from occurring?
My overflow on the temporary pest tank uses an aqualifter to maintain siphon. No issues stopping at all unless I let the overflow get dirty. Only maintenance is cleaning occasionally and changing out air tubing if it gets clogged- which has only happened once in last 1.5 years and siphon still held. So no tank issues.

I don’t know

 

[sharis100]

I don’t know

So, only certain overflows have this feature built in and if you are going hob overflow - I highly recommend this type so that siphon is not lost. CPR has kits and Lifereef makes a great one too.
Here is an older write up for the most still valid:

Reliable HOB Overflow Guide

Disclaimer: If you have the option (at all) of getting an internal overflow or a glass-holes style overflow - GO THAT ROUTE!!! It is a far better, far cheaper solution. However, It's been over a year since I've put this HOB on my tank and about 2 months since I converted it to run on FULL SIPHON ...

www.nano-reef.com

 

[samsisson]

So, only certain overflows have this feature built in and if you are going hob overflow - I highly recommend this type so that siphon is not lost. CPR has kits and Lifereef makes a great one too.
Here is an older write up for the most still valid:

Reliable HOB Overflow Guide

Disclaimer: If you have the option (at all) of getting an internal overflow or a glass-holes style overflow - GO THAT ROUTE!!! It is a far better, far cheaper solution. However, It's been over a year since I've put this HOB on my tank and about 2 months since I converted it to run on FULL SIPHON ...

www.nano-reef.com

I like my CPR beats drilling a tank thats full of livestock!

 

[NanCrab]

I will look at it thank you!!! Been busy, my little toy poodle had to have reconstructive knee surgery on Friday and the poor little guy has been in so much pain!! He seems a lot better today though!
Thanks for all of the responses, I will look into all these different ideas. I am inexperienced- only had the drilled 125 and used a HOB filter when it was a QT tank. Appreciate everyone’s help!!!

 

[NanCrab]

Does it need to be controlled on both the uptake and discharge? Couldn't you just put a ball valve in the return and a T that returns to the sump right before it?

We have a gate valve on the pump side and a ball valve on the drain side. I think I’ve identified a couple of issues. The section of the sump where the water drains in from the tank is very narrow and I cannot fit 4” socks or filter cups in there. I’ve been putting polyfil in there and it seems like it can get pushed into the slot where the water flows from that section to the next. Also, I had the pump plugged into a WiFi power strip. We’d had a power surge and I believe the plug shut itself off so the tank started draining rapidly. There’s no siphon break so the sump was going to overflow. Thankfully I was right there and was able to act quickly to avert disaster. That’s why I was asking if there was a way to add a siphon break.
Im going to look into the different products suggested in the thread because I definitely can’t trust what I’ve got.
Thanks!