Help - warter level issues

[dfm34]

So here are the details that I need some experts to help me figure out. My tank has been up and cycled for about two months. Starting this week I have noticed that the water level in my sump is fluctuating wildly. The level in the sump will raise and drop to the point my pump (Mag9) starts to run dry or the return in the display will be above the water level. I know it is not normal evaporation as it happens too fast and will swing between too low or too high. I have turned off my ATO to prevent too much fresh water flooding the sump on the low swing. The only thing I have added recently is a CUC. Any ideas on why the sudden change. Thanks in advance.

[fishgate]

If your flow is right on the cusp between flowing and full siphon that could cause what you are seeing. Try reducing your flow back to the DT.

[dfm34]

If your flow is right on the cusp between flowing and full siphon that could cause what you are seeing. Try reducing your flow back to the DT.

I do have a ball valve on the return but have not touched it until this started. Thought I had it dialed in since its been two months wit no issues. To further complicated matters this weekend I am adding a skimmer so I really want to work this out first.

[fishgate]

What kind of overflow do you have? Drilled/HOB? Have you accounted for all of your CUC?

[dfm34]

Drilled 75 gal deep blue tank. Bought the 30 cuc from reef cleaners way too many to count. Where would a snail get caught??? Would it make it down overflow through all 3 sump chambers to return pump?????

[Cymonous]

You might have a snail in the drain plumbing causing a plug.

[Breadman03]

You might have a snail in the drain plumbing causing a plug.

That would be the first thing that I would check.

You didn't mention what type of drain you have setup (Durso/Bean/etc.). I had a problem with my Durso where my return was pushing slightly more than the line could handle, so I would end up with a full siphon for a few seconds a few times an hour. I was also getting too much flow through my skimmer chamber and sucking micro bubbles into the tank, so I teed off my return line to slow the flow through the tank and skimmer chamber while keeping moderate circulation through the LR in my sump.

[dfm34]

That would be the first thing that I would check.

You didn't mention what type of drain you have setup (Durso/Bean/etc.). I had a problem with my Durso where my return was pushing slightly more than the line could handle, so I would end up with a full siphon for a few seconds a few times an hour. I was also getting too much flow through my skimmer chamber and sucking micro bubbles into the tank, so I teed off my return line to slow the flow through the tank and skimmer chamber while keeping moderate circulation through the LR in my sump.

It's a durso and you may be on to something every now and then I would hear a sucking sound from my return. So just to make sure I understand you teed off the return line in the DT not the drain line in the sump.