Return pump fluctuating speed

[Pennywise the Clown]

I run a Jebao DC4000 return pump in my Reefer 250.
I am constantly having to mess with the Red Sea flow valve as the water level in my overflow is always rising. I set the level to half an inch under the emergency overflow and within a few hours it is overflowing,
I originally thought that this was a problem with the valve but this has been cleaned and is definitely working as intended.
My only thought is that it must be the return pump slowly ramping up in speed. This issue is driving me mad because it is hard to keep my salinity stable because as more water gets pushed into the display, my ATO is topping up my tank.

 

[ca1ore]

Just keep in mind that even really tiny variations in pump performance are enough to throw off a herbie/bean - doubt the pump is ramping per see, but there will always be micro variations. Heck even a clump of algae on the pump intake strainer may be enough to throw off the drain system. I always run my siphon drain systems with a slight trickle through the secondary/emergency. I know some folks object to this approach, but I've never found it to affect the safety of the system and it eliminates the fiddling.

 

[Pennywise the Clown]

Just keep in mind that even really tiny variations in pump performance are enough to throw off a herbie/bean - doubt the pump is ramping per see, but there will always be micro variations. Heck even a clump of algae on the pump intake strainer may be enough to throw off the drain system. I always run my siphon drain systems with a slight trickle through the secondary/emergency. I know some folks object to this approach, but I've never found it to affect the safety of the system and it eliminates the fiddling.

Thanks for the reply.

I can set the level to a slight and silent trickle. The problem is that after a few hours it becomes a noisy gush of water.

 

[Tastee]

I run the Jebao DCT 3000 on my RSR 250 and I feel the fluctuations I get are more to do with algae growth. It is only in the last 3 months that I have got the tank to a level of stability I am happy with and since then the overflow level has been fairly stable. I can only recall adjusting it twice in the last 3 months. Prior to that I was adjusting it every couple of weeks.

The next time I clean the return pump I expect to need to re-tune this, and probably tweak it once or twice more in the couple of months after as a bit of algae growth comes back.

 

[Pennywise the Clown]

I run the Jebao DCT 3000 on my RSR 250 and I feel the fluctuations I get are more to do with algae growth. It is only in the last 3 months that I have got the tank to a level of stability I am happy with and since then the overflow level has been fairly stable. I can only recall adjusting it twice in the last 3 months. Prior to that I was adjusting it every couple of weeks.

The next time I clean the return pump I expect to need to re-tune this, and probably tweak it once or twice more in the couple of months after as a bit of algae growth comes back.

That's interesting because I'm fighting some hair algae at the moment.
How do feel that algae affects the fluctuations in the pump?

 

[Tastee]

That's interesting because I'm fighting some hair algae at the moment.
How do feel that algae affects the fluctuations in the pump?

I don’t know that the pump fluctuates that much. I expect that after new or a clean it will build up a small algae/slime coat over time but given the high flow through a small area that should be minimal and only grow gradually over time. Calcium will also build up particularly around the impeller gradually, probably slowing flow a little over time.

The bigger algae/slime buildup will be in the piping/tubing. That will restrict flow back from the return and down through the overflow. This is what I feel impacts stability of the overflow level most. I feel that now my tank is more stable the algae quickly builds to it’s ‘normal’ level and then pretty much stays there, with only gradual changes. Prior to this point I felt it came and went as the tank itself fluctuated.

 

[Tyler White]

I have the exact same pump and it does the same thing for me. BUT the last day or so it hasn't actually gone out of wack. Not sure how long your tank has been running but somehow it might just be a break in issue. My system has been running for about a month.

 

[Pennywise the Clown]

I have been off work today and the water level has stayed stable, half an inch under the overflow, all day. Then, at 2pm, the water level rose suddenly and my ATO dumped a ton of water into the sump. Now water is surging down the emergency overflow.
What is going on?