Help please. Cade ATO back syphoning

[SimBZ]

Hello everyone and greetings from Aus,
I need help please!
I am new to having a tank with a sump.
I have a cade with a gravity fed ATO sitting behind the DT.
Yesterday I did the first water change after the cycle has completed. I made marks on the sump for running levels and shut down level.

I made an error in using a different bucket for calculating exported water to the bucket i used to refill, which resulted in a low level in the return pump well (where the ato float sits). I added more water to the return well.

This morning i have woken to "brook like" sounds and discovered the ato float totally out of water ( with only drips falling) and the ATO behind the DT has filled with water to the same level as the DT.
I touched the float and now the level in the ATO is lowering.

Did I put too much water back into the system?

How did the back syphoning occur and how do I stop it from happening again?

Thank you,
Simone

 

[KrisReef]

Can you post a picture of your set up for us dim folks who cant make out what the words on the screen mean?

I had a flood recently and I hate to say it but I am glad it was you this time. It gets old my friend. Post a picture or someone with your system will be along shortly- bump!

 

[SimBZ]

 

[SimBZ]

The pictures shows the setup. No frills. Low water and after the Auto Top Up filled up the return chamber. Apologies for non standard descriptions.

 

[KrisReef]

I'm recovering from the flu and I am not familiar with the set up so the pictures are helpful.

I am feeling better today, so let me offer another perspective. Auto top offs will operate during water changes and start to refill the sump if you are removing water from there?

When I do a water change, I add water (~5 gallons at a time) to the sump (with the pumps shut down) and then remove the same amount of water from the DT. I turn the pumps back on, let it cycle and do another 5 gallons. This way, the sump never empties and the ato doesn't come on.

I also have a cap that I can cover the inlet to the ato so that If I am doing really large water changes the ato is isolated and will not put water out while the sump levels goes where ever. If I forget to cap the ato doing a large water change after the process is done and the system has been running a few minutes I check salinity and will add (slowly) some hyper saline mix back into the sump to get the salinity back on target. Then I remove excess water until the ATO float is active again.

hth

 

[Kmst80]

Hi Simone,
i got a Cade pro reef 900.
Did you take water out of the sump? Did you shut everything down first?
So here is how i do waterchanges:
First everything except the lights i turn off, heaters, chiller, skimmer, wavemaker and last return pump.
After that the sump fills up with water till the returnoutlet in the DT is out of the water.
Then i take out x amount of water from DT, and fill with x amount of prepared water in DT.

 

[MmeAssoc]

Hi,

I have a Cade 900 S2, and I don't understand how it could back-siphon: that would require water to flow against gravity, and travel up a pipe without a pump.

What it seems could happen, is water could overflow from your weir into the ATO - they're separated by a divider that is lower than the overall walls of the tank. So if your gate valve was just about closed and the emergency drain was somehow blocked, maybe salt water could back up in the weir and overflow? Although the emergency drain should take care of things if your main drain wasn't open enough - unless your whole system was overfilled to a point where it could flow over the weir divider and into the ATO?

Sorry I can't be of more help - I hope someone else has the answer to what happened here, I'm keen to understand.

 

[MBReefers]

Hi. I appreciate this is an old post but did you get to the bottom of it?
I’ve just got a cafe S2 1500 and had the same issue. I can’t understand how water can go up the pipe and I expect the float valve would be shut so it shouldn’t anyway. The main drain and emergency drain are balanced nicely with the main drain doing all the work and the emergency drain sitting just above the surface.
The only thing I can think of is the nozzle fitting for the return pump that goes through the bulkhead between ATO and the DT. If that’s passing then it will cause the 2 to level out. That’s all I can think of so that’s tomorrows mission to find out.