Water level issues

Claus84 · Dec 22, 2018

Hi all,

I'm having problems with the plumbing on my new 300g that i'm hoping someone can shed some light on. I'm finding it very frustrating trying to balance my water level. For example I topped my sump this morning, and it immediately dropped back to its previous level sending the extra water up into the DT instead for some reason. I've provided all the relevant info I can think of below.

- Tank = 96x24x30
- Sump = 70x18x18
- 2 x Fluval SP4 return pumps (7000lph / 1850 US GPH each)
- Twin overflow - 2 x 40mm main drain (3"below waters surface) / 2 x 40mm emergency (dry)
- Left hand drain has a straight drop to the sump
- Right hand drain has a 6ft horizontal run to the 1st sump chamber - angled v.slightly downwards.
- Both main drains are controlled by ball valves (no valves on emergency's) and the pipes exit 1" under the water level in the sump

I have my suspicions that I just have too much flow going through the system, tried it with just one return running but it isn't enough to force the air out of the long horizontal run from the right hand drain and its constantly 'coughing' (aspirating??!) into the sump. Also the water line is visible in the DT with only one pump running, for some reason the manufacturer has left very little tolerance in the pelmet design so there must be a certain amount of flow backing up against the weirs or the WL is visible, which drives me insane!

Getting the water levels correct in the weirs was also a huge PITA which again makes me think i'm running too much flow for the system. Even the slightest adjustment to one of the ball valves either raises the DT level too high stopping any surface skimming or the weir level too low and the drains start to suck in air.

Hopefully someone out there can tell me where I am going wrong

Thanks

Nick

acabgd · Dec 22, 2018

Some photos would certainly help although I already feel the problem lies with the ball valves.

Claus84 · Jan 6, 2019

acabgd said:
Some photos would certainly help although I already feel the problem lies with the ball valves.

Thanks for the response and sorry for the delay. I've taken a short video which I will hopefully link below to explain what's going on and show the setup.

Claus84 · Jan 6, 2019

Flexin · Jan 6, 2019

The ball valves, are they on the inflow into the sump or the return to the DT? Also, what does the overflow look like in the DT? Can you take a picture of that and how the pipes are layed out up there please.

Claus84 · Jan 6, 2019

Flexin said:
The ball valves, are they on the inflow into the sump or the return to the DT? Also, what does the overflow look like in the DT? Can you take a picture of that and how the pipes are layed out up there please.

The ball valves are on the main drains, I use AC return pumps and don't have any valves on these so no way to alter flow.

Not sure exactly what you need to see but I've attached a photo which will hopefully help

Thanks

acabgd · Jan 6, 2019

I must say I don't have experience with two overflows on two different sides of the tank. Are both your return pumps in the same section of the sump? With all the flow you have there should be no problem with two overflows which should have enough throughput. As you're saying, there might be an air pocket in the right drain due to the horizontal section of it, but it's more than I'd know due to the double overflow layout. My understanding would be the other (left) overflow should take over the brunt of the drain without affecting the water level in the display. Maybe someone else can chime in.

Flexin · Jan 6, 2019

Have you tried to open both valves to the sump wide open?

Flexin · Jan 6, 2019

I thought ball valves should go on the return. When they are only on the inflow to the DT you can end up with it overflowing in the DT either by the valve being closed too far or something gets caught.

Claus84 · Jan 7, 2019

Flexin said:
I thought ball valves should go on the return. When they are only on the inflow to the DT you can end up with it overflowing in the DT either by the valve being closed too far or something gets caught.

That's what the emergency drains are for, in the event that one or both of the main drains get blocked the emergencys can handle the flow preventing a flood.

Valves are needed on the drains to control the water height in the overflow, I will be switching out the ball valves for gate valves so I can adjust more precisely. I don't think the valves are the cause of the fluctuation though but could be wrong.

For now I have changed one of my dry emergencies to wet with a trickle of water and a durso which should account for any fluctuations whilst I figure out what's going on

Thanks

Billldg · Jan 7, 2019

Sounds to me like you have an imbalance between your drain and return, I have to meter the hand valves on my drains to balance out my water level, if I don't it will suck my return section dry. If i have the drain line hand valves open to much it will suck my drains dry. It's a balancing act between the two.

Maybe the #reefsquad has some answers.

TheEngineer · Jan 7, 2019

Dual overflows are always a pain to balance. The first thing that I'd try is to confirm your suspicion about an air bubble on the right side. I'd close off the drain on the left completely and try to just tune the right side. You'll be able to see if you are indeed getting a bubble stopping your flow.

Claus84 · Jan 7, 2019

TheEngineer said:
Dual overflows are always a pain to balance. The first thing that I'd try is to confirm your suspicion about an air bubble on the right side. I'd close off the drain on the left completely and try to just tune the right side. You'll be able to see if you are indeed getting a bubble stopping your flow.

Hmm so I did as you suggest and closed off the left hand overflow, tuned the right side till there was a slight drip coming down the emergency drain. As you'd expected the water level in the sump return section dropped as the closed overflow was holding more water up top so I topped the sump up. After topping the sump up the emergency drain is now a constant trickle rather than a drip and the level in the return section of the sump has dropped back down very slightly. The overflow must be holding just a few mm more water than it was before topping the sump up, could this be indicative of an airlock in the pipe or something else?

I'll keep monitoring the level for a while and then i'll try the same with the other overflow.

Thanks

acabgd · Jan 7, 2019

Claus84 said:
Hmm so I did as you suggest and closed off the left hand overflow, tuned the right side till there was a slight drip coming down the emergency drain. As you'd expected the water level in the sump return section dropped as the closed overflow was holding more water up top so I topped the sump up. After topping the sump up the emergency drain is now a constant trickle rather than a drip and the level in the return section of the sump has dropped back down very slightly. The overflow must be holding just a few mm more water than it was before topping the sump up, could this be indicative of an airlock in the pipe or something else?

I'll keep monitoring the level for a while and then i'll try the same with the other overflow.

Thanks

Are you sure you have enough water in your system? It kinda sounds to me as if there's not enough water there, but I must admit I still don't quite understand what's going on here.

Claus84 · Jan 7, 2019

acabgd said:
Are you sure you have enough water in your system? It kinda sounds to me as if there's not enough water there, but I must admit I still don't quite understand what's going on here.

Yeah there is definitely enough water but with the ball valves and the amount of flow I have from 2 7200lph returns it is a very fine balance, the gate valves should help with though I'm hoping

TheEngineer · Jan 7, 2019

Claus84 said:
Hmm so I did as you suggest and closed off the left hand overflow, tuned the right side till there was a slight drip coming down the emergency drain. As you'd expected the water level in the sump return section dropped as the closed overflow was holding more water up top so I topped the sump up. After topping the sump up the emergency drain is now a constant trickle rather than a drip and the level in the return section of the sump has dropped back down very slightly. The overflow must be holding just a few mm more water than it was before topping the sump up, could this be indicative of an airlock in the pipe or something else?

I'll keep monitoring the level for a while and then i'll try the same with the other overflow.

Thanks

Does not sound like an air problem then. You'd be running your emergency drain full speed, not just a trickle.

The fact that one drain is capable of handling all of your flow that means you will need to close both the drains at least half way.

Claus84 · Jan 7, 2019

TheEngineer said:
Does not sound like an air problem then. You'd be running your emergency drain full speed, not just a trickle.

The fact that one drain is capable of handlin all of your flow that means you will need to close both the drains at least half way.

Yeah both of my main drain ball valves are just over half way closed, I guess i'll switch out the ball valves for gate and see if that helps at all. At least for now running one emergency as a wet durso will mean I can keep the sump level pretty constant and set my ATO up. I guess in essence I now have a bean animal setup but split over 2 overflows and with 2 siphon drains?

Thanks for your help

TheEngineer · Jan 7, 2019

Two pumps and two drains, you've got yourself a multivariate problem to solve :)

Williamson’s Reef · Mar 5, 2019

Once you get your drains adjusted/quiet... then set the water level in your sump/whole system. Add or subtract water to get there. Then set ATO to that level. A little trickle down the emergency drain is ok if that’s what it takes.