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View Full Version : What cause sudden skimmer flooding


BlackTip
02/11/2016, 08:54 AM
My skimmer has been running for at least 3 weeks without any adjustments. I get about 2-3" of skimmate every 2-3 days or so, that's when I take the cup out, empty it, and clean it. I cleaned the cup last night.

This morning, I received an apex flood alert. I rushed downstairs and I found the skimmer has flooded. The skimmer sets inside the sump, but it was obvious that the skimmer was pumping a lot of water. The collection cup was full of clear and clean water, and there was splashing everywhere. About a glass full of water made it to the cabinet floor, and that is when my leak detector kicked in and shut everything off.

I didn't change or do anything to the system. I did water change on Monday and added a small amount of carbon in a sack. On Tuesday, I took the mesh sock out, cleaned it, and put it back. I clean it with tap water, and I have been doing this without any problems.

I have a light bio load. 9 small fishes and few cleanup guys.

What could cause the skimmer to flood like that?

wildman926
02/11/2016, 10:25 AM
If the skimmer's water level is set too high internally, it will overflow when the "system" takes a big dump. SRO's are notorious for overflowing.

drew2007
02/11/2016, 10:30 AM
Could also happen if the Venturi and/or airline is clogged. Salt creep, calcium deposit, etc. check that out and run some hot tap water through the them and clean them out. My reef octopus was notorious for that happening.

BlackTip
02/11/2016, 10:33 AM
SRO's are notorious for overflowing.

This is news to me. Before buying, I did a lot of research and it was one of the most recommended skimmers. I don't remember reading anything about overflowing.

If I keep the internal water level at the bottom of the neck as recommended, the gunk collects in the neck and doesn't go to the collection cup.

slief
02/11/2016, 10:52 AM
Could also happen if the Venturi and/or airline is clogged. Salt creep, calcium deposit, etc. check that out and run some hot tap water through the them and clean them out.

+1.. Salt creep in the venturi line will cause this as well as something like a snail or debris getting into the pumps intake. If you sump level hasn't changed or you aren't encountering a bacterial bloom or you didn't use Epoxy or something else that could have changed the waters surface tension, I would suggest removing the pump and taking it apart to inspect for salt creep or clogging where the air hose connects to the pump and also make sure something didn't get scuked nto the impeller area of the pump.

BlackTip
02/11/2016, 11:09 AM
About a month ago, I took the skimmer apart and cleaned it thoroughly with water/vinegar, I didn't clean the air hose though; I was afraid vinegar might damage the silicone hose. After cleaning, it became unstable for couple of weeks (overflowing every night), and now I think it is doing the same thing again after two weeks of stability. External water level doesn't change ever, and I didn't use epoxy in the tank for at least a month.

I am gonna have to inspect and clean the air line and venture this weekend.

slief
02/11/2016, 11:18 AM
About a month ago, I took the skimmer apart and cleaned it thoroughly with water/vinegar, I didn't clean the air hose though; I was afraid vinegar might damage the silicone hose. After cleaning, it became unstable for couple of weeks (overflowing every night), and now I think it is doing the same thing again after two weeks of stability. External water level doesn't change ever, and I didn't use epoxy in the tank for at least a month.

I am gonna have to inspect and clean the air line and venture this weekend.

It's not likely the airline but instead where the airline connects to the pump. The plastic ports were the airlines connect to skimmer blocks are notorious for getting salt creep in there. Vinegar won't necessarily remove that either. I usually suggest a tooth pick to remove any salt creep. Occasionally running some scalding hot water through the venturi line will help mitigate that too. I just take a cup of hot water and stick the venturi line into the cup and allow it to suck the water through while the skimmer is running. That tends to remove some of the salt creep buildup but regular inspection of the venturi port when you clean the pump is a must with any skimmer pump. As such, remove the pump, and inspect the venturi port as well as inside the needle wheel area inside the pump. A small bit of debris or a critter in there will cause overflow symptoms as will salt creep in the venturi port.

Vinny Kreyling
02/11/2016, 11:25 AM
I use a drill bit & turn it with my fingers to clean the ports.
You just need to get the right one.
If it falls in between 2 standard drills there are # drill sizes available.

m3lacoste
02/11/2016, 11:47 AM
Did your return pump shutoff and then turn back on, raising the level in your sump? My skimmer will overflow when this happens because the water level gets too high.

wildman926
02/11/2016, 01:39 PM
This is news to me. Before buying, I did a lot of research and it was one of the most recommended skimmers. I don't remember reading anything about overflowing.


You missed it big time. Here is a quick search from google of "sro overflowing" -

https://www.google.com/search?q=sro+overflowing

Cleaning the air tube on the volute is done automatically when you shut off the skimmer for your cleaning, which sounds very regular. Watch when you turn it off, water goes almost all the way to the silencer.

slief
02/11/2016, 01:52 PM
You missed it big time. Here is a quick search from google of "sro overflowing" -

https://www.google.com/search?q=sro+overflowing

Cleaning the air tube on the volute is done automatically when you shut off the skimmer for your cleaning, which sounds very regular. Watch when you turn it off, water goes almost all the way to the silencer.

The flooding of salt water in the lines won't remove the salt creep. In fact, it may actually exacerbate the issue as the salt from the water flooding the lines tends to dry out inside the air intake where that line meets the pump and collect there and will continue to build up over time.

The salt buildup reduces the venturi orifice size restricting the airflow. When the airflow is reduced from the salt restriction, the water flow into the skimmer is increased. Air normally displaces the water flow through the pump and when the air line is restricted, that missing air is replaced with additional water flow which causes in increase in the skimmers water level. Also, when the pump is running, there is a small amount of water that makes it up the edges of the venturi inlet on the pump. The air passing through it facilitates the salt drying in the venturi port which builds thicker overtime. Flooding the lines when you shut the pump off will not remove much if any of the dried salt either. It generally needs to be manually removed. This has been the case with virtually every skimmer I have ever owned.

wildman926
02/11/2016, 02:31 PM
The flooding of salt water in the lines won't remove the salt creep. In fact, it may actually exacerbate the issue as the salt from the water flooding the lines tends to dry out inside the air intake where that line meets the pump and collect there and will continue to build up over time.

The salt buildup reduces the venturi orifice size restricting the airflow. When the airflow is reduced from the salt restriction, the water flow into the skimmer is increased. Air normally displaces the water flow through the pump and when the air line is restricted, that missing air is replaced with additional water flow which causes in increase in the skimmers water level. Also, when the pump is running, there is a small amount of water that makes it up the edges of the venturi inlet on the pump. The air passing through it facilitates the salt drying in the venturi port which builds thicker overtime. Flooding the lines when you shut the pump off will not remove much if any of the dried salt either. It generally needs to be manually removed. This has been the case with virtually every skimmer I have ever owned.

You are correct about what happens if the air is blocked. And you are correct that this will happen, if you never shut off your skimmer, or once in a blue moon. I have tested this "theory" since I have a skimmate waste collector, and have no need to shut off the skimmer other than to clean the collection cup/neck. Salt will build up in the air tube of the volute after a months of non stop running. But bi weekly cleanings of the neck/cup, it never builds up due to the backflush. I am speaking from experience.

The OP cleans/empties his cup regularly, "every 2- 3 days", which is enough to have the same results of a backflush to clean the air tube on the volute. I bet when the OP checks it, it will be clean.

I have had a couple of SRO's. Their shape and massive air draw, induces overflows when the internal level is set high. A quick fix is to put an air valve to restrict the air to create smaller air bubbles, for better control.

BlackTip
02/15/2016, 10:44 AM
So, I cleaned the skimmer this past weekend, and what I found was a white deposit in front of the venturi air opening effectively reducing the capacity of air intake. I was not able to remove it with neither hot water nor water/vinegar mix. I had to pry it out with very small screw driver. It can't be salt, so I think it was calcium deposit. The skimmer didn't overflow last night, so I am crossing fingers. Also, this could solve my fresh air intake issue I posted last month. It is connected to the fresh air intake, and I am watching to what is going to happen next.

Again and again Slief called this right, thank you sir, and thanks to everyone who responded to this thread.