Overflow flucuation with flushing sound

[afamousjohnson]

I have been going crazy with the tank these past few days - im sure a few of you can relate lol.

1st thing 1st - this is NOT a new system. Has been running close to 2 years and during those 2 years has run dead silent.
Have the durso overflow - proper pvc sizes for overflow and return - hole drilled at top of overflow with tube inserted for air assistance - drain inch or so under water in sump - overflow piping at angles down to sump etc etc etc.

The other day I put my arm in the tank to grab an acan that had fallen. This must have raised the level and my overflow started surging. Okay - shut down return - let drain and started it over. That worked.
Same instance again next day with arm in tank. Tried shutting down again - didnt work.
Closed ball valve on return slightly (system runs 2 tanks along with an open loop down in sump for recirculation so no probs with dialing return down a bit) That worked temparaily. It started again. Tried that again and didnt work this time.
So next troubleshooting dialed back return pump (have a DC) This worked temparaily again. Yet once again next day started again. Now im at my wits end.
Other trouble shooting now today. messed with DC again now on lowest setting - nope - raised it back to normal setting - nope - sprayed water down airline in overflow elbow in overflow chamber in case of salt build up clogging - nope - added extension tube to airline to raise above surging water nope - blew air in airline to see if that helped - nope
did everything over one last time and in cosecutive sequence - hmmmm its quiet again and not surging or flucuating.
But now I dont want to shut down return or dare put my arm in the tank

Any ideas on what could be happening - other things to look at related to situation?
So frustrating. I dont like that i now have to have not only the return line to that tank slightly closed along with having to run my DC return on its lowest setting. Espescially since it has run flawless for 2 years
Any Ideas
Thanks all

 

[Eienna]

Clean out the pump. If its speed is fluctuating that can cause the problem. I just had to deal with this on mine XP

 

[Eienna]

Oddly enough, it was a DC pump too. I wonder if sometimes the power fluctuates in the house and causes this?

 

[morpheas]

My guess is that there is buildup somewhere in the hydraulics, either the return or most probably drain. Is it an option to take the drain apart and check? Have you ever done this? Maybe something went down and got stuck? Any 90's on the drain?

From your description it sounds like the system is at it's draining capacity. If all piping is appropriate sizing etc (which you said it is) I would strongly suspect buildup (calcium, sludge etc) or clog (snail or something).

 

[Eienna]

It just hit me - isn't house power AC? If so, our converters on the cords may not be working right, causing the power to the unit to remain AC. That would cause it to receive power in waves...

 

[afamousjohnson]

Thanks for the replies.
Ya when I made the plumbing it was set up to be "easier" to remove for matainance lol I have not removed overflow or cleaned return tho the thought was there. When I was thinking this I decided to check the drain capacity so I left return on and closed overflow ball valve completelty letting the tank fill up above where it should be. I than opened overflow valve and it instantly drained back down to surging / normal level leaving me thinking the drain is clear.
With return pump wouldnt it be loosing power tho instead of gaining flow putting more water into tank than drain is set for?
Either way the return pump could use a clean along with pipe checks to make sure its all on the up and up - just hate doing those chores lol
So weird that it has finally quieted down again and holding all levels at marks without any flucations. Looks like today just added to the project list

 

[morpheas]

I know what you mean, my access to my return is not so good so cleaning it sounds like a nightmare... Regardless if you find anything or not doing a good cleanup will give you a sense of accomplishment at the end haha [emoji4]

 

[Eienna]

Thanks for the replies.
Ya when I made the plumbing it was set up to be "easier" to remove for matainance lol I have not removed overflow or cleaned return tho the thought was there. When I was thinking this I decided to check the drain capacity so I left return on and closed overflow ball valve completelty letting the tank fill up above where it should be. I than opened overflow valve and it instantly drained back down to surging / normal level leaving me thinking the drain is clear.
With return pump wouldnt it be loosing power tho instead of gaining flow putting more water into tank than drain is set for?
Either way the return pump could use a clean along with pipe checks to make sure its all on the up and up - just hate doing those chores lol
So weird that it has finally quieted down again and holding all levels at marks without any flucations. Looks like today just added to the project list

It would be losing power (hence the flush) and then gaining it (refilling the overflow) in fairly quick cycles. Honestly I wouldn't have minded too much if it wasn't so loud. Gave it a waveish action that my corals really seemed to like.