UNEQUAL WATER CHANGE

[Icedog]

About four months ago I set up my first reef tank - it's a 54 gallon display tank with an EShopps RS-75 sump and a Bubble Magus protein skimmer underneath. I've been doing biweekly water changes of approximately 10%. That is, I siphon out 5 gallons of water from the display and add 5 gallons of fresh salt water back into the sump. But after I do this I see that the water level in the sump is much higher than it was before the water change, and this seems to wreak havoc on my protein skimmer.

Initially I thought that it would take awhile for the return pump to equilibrate the system, but even after several days the water level in the sump is still higher than it should be. I also checked the calibration of the pail I used to hold the siphoned water and the contents of the jug I used for the fresh salt water - both were 5 gallons.

I then spoke with my lfs about this and I was told that this was a common reef fact-of-life - you can't put as much salt water back in as you took out! It was suggested that I remove 5 gallons of tank water and add back in 4 gallons of fresh salt water.

Am I doing something wrong in my method of water-changing? At my next water-change I'm going to try adding the fresh salt water to the display tank (instead of the sump) to see if this makes a difference. But any other suggestions would be helpful . . .

Or is the info the lfs gave me true? If so, can anyone explain the physics of this for me? Where does that 0ne gallon go?

 

[Crabs McJones]

Welcome to R2R!

#WelcometoR2R

Are the buckets the same size? Ones not taller or bigger in diameter than the other? Because that doesnt make sense to me. If you take out 5 gallons of water you should be able to put back in 5 gallons of water and be at the same water level.

 

[Peach02]

About four months ago I set up my first reef tank - it's a 54 gallon display tank with an EShopps RS-75 sump and a Bubble Magus protein skimmer underneath. I've been doing biweekly water changes of approximately 10%. That is, I siphon out 5 gallons of water from the display and add 5 gallons of fresh salt water back into the sump. But after I do this I see that the water level in the sump is much higher than it was before the water change, and this seems to wreak havoc on my protein skimmer.

Initially I thought that it would take awhile for the return pump to equilibrate the system, but even after several days the water level in the sump is still higher than it should be. I also checked the calibration of the pail I used to hold the siphoned water and the contents of the jug I used for the fresh salt water - both were 5 gallons.

I then spoke with my lfs about this and I was told that this was a common reef fact-of-life - you can't put as much salt water back in as you took out! It was suggested that I remove 5 gallons of tank water and add back in 4 gallons of fresh salt water.

Am I doing something wrong in my method of water-changing? At my next water-change I'm going to try adding the fresh salt water to the display tank (instead of the sump) to see if this makes a difference. But any other suggestions would be helpful . . .

Or is the info the lfs gave me true? If so, can anyone explain the physics of this for me? Where does that 0ne gallon go?

by fresh salt water do you mean freshwater mixed with salt or new saltwater?
usually I take it out of the display tank after turning the pump off, old water goes into a bucket, I put new saltwater into a bucket up to the same level and slowly pour the new saltwater back in, and turn the pump back on, nothing goes wrong, the sump water level rises when the pump is off but in no danger of overflow

 

[reef lover]

Welcome to r2r !

 

[Peace River]

Am I doing something wrong in my method of water-changing? At my next water-change I'm going to try adding the fresh salt water to the display tank (instead of the sump) to see if this makes a difference. But any other suggestions would be helpful . . .

Or is the info the lfs gave me true? If so, can anyone explain the physics of this for me? Where does that 0ne gallon go?

Um . . . somethings missing in this equation. I'm pretty sure that 5>4.

Just to double check, you may want to turn off the pump and let the water settle, remove 5 gallons of water from the main tank, add 5 gallons of new saltwater to the main tank, and then restart the system. If you get anything other than the same exact levels then repeat the process on camera and share the video because otherwise the "maths" doesn't add up!

If the LFS were talking about adding a gallon of RO water to make up for evaporation and then removing 4 gallons of tank water and adding 4 gallons of new full-strength saltwater then that is math that makes sense. Good luck!

Oh, and check for leaks. Do you see a puddle of a gallon of water anywhere on the floor? Just kidding.

 

[Icedog]

Welcome to R2R!

#WelcometoR2R

Are the buckets the same size? Ones not taller or bigger in diameter than the other? Because that doesnt make sense to me. If you take out 5 gallons of water you should be able to put back in 5 gallons of water and be at the same water level.

Yes, I checked that. I usually get 2.5 gallon jugs of fresh saltwater from my lfs and use a 3 gallon pail with volume markings for the siphoning off part. One time I took an empty one of the 2.5 gallon jugs, filled it up to the 2.5 gallon mark and emptied it into the 3 gallon pail. The pail filled up to the 2.5 gallon mark.

 

[Icedog]

Welcome to r2r !

Thanks! I'm really enjoying all of these quick responses!

 

[Dual40IM]

My suggestion is to mark the sump in the return section and refill to the same mark once the pump is turned back on. I hate math so that is how I do it. lol
Do you have an auto top off? If not then the evaporation would explain why you math does not add up. If you are not running an auto top off check your salinity immediately. Adding saltwater back in will only increase your salinity and that is not good. Best of luck and let us know if you figure anything out.

 

[Icedog]

Um . . . somethings missing in this equation. I'm pretty sure that 5>4.

Just to double check, you may want to turn off the pump and let the water settle, remove 5 gallons of water from the main tank, add 5 gallons of new saltwater to the main tank, and then restart the system. If you get anything other than the same exact levels then repeat the process on camera and share the video because otherwise the "maths" doesn't add up!

If the LFS were talking about adding a gallon of RO water to make up for evaporation and then removing 4 gallons of tank water and adding 4 gallons of new full-strength saltwater then that is math that makes sense. Good luck!

Oh, and check for leaks. Do you see a puddle of a gallon of water anywhere on the floor? Just kidding.

LOL! One of my first thoughts was a leak, too! But I'm okay there - no leaks. And I think the LFS understood that I was talking about a water change and not adding any RO water for evaporation. It kind of surprises me, though, that the LFS seemed to think that this is a common issue and after seeing these responses to my post, it doesn't seem to be. No wonder I can't find anything on the internet about this!

With my next water change I will add the fresh salt water back to the main tank instead of the sump - hopefully, that'll help.

Thanks for your suggestions.

 

[Peace River]

Thanks! I'm really enjoying all of these quick responses!

That’s how we roll!

 

[Mastiffsrule]

Um . . . somethings missing in this equation. I'm pretty sure that 5>4.

Too funny and too true. Still lol

We welcome you to the community. You are on point. If you take out 5 and put in 4 = empty tank eventually. (Peace river not only one can do math)

It can throw you off a bit if you fill up one before the other. What I usually do is turn off my pumps before the change. Water drains back into the sump. Then I do the change in DT. I add water to the DT to about the normal level. I stop filling once near top level and turn on the pumps. The sump will pump the wate in the tank. If you are even then all set. If the sump water level after it is running then it is high and drain a bit out. Usually when I fill I leave a few gallons short when I fill. Then I hit the pump on. All the water drains from the sump and The pump starts shooting bubbles and I add more to the sump until I get the right level

And WELCOME

 

[Icedog]

My suggestion is to mark the sump in the return section and refill to the same mark once the pump is turned back on. I hate math so that is how I do it. lol
Do you have an auto top off? If not then the evaporation would explain why you math does not add up. If you are not running an auto top off check your salinity immediately. Adding saltwater back in will only increase your salinity and that is not good. Best of luck and let us know if you figure anything out.

I don't have an auto top off. Instead I have marks on the return section of the sump and manually fill with RO water every few days to keep the water line between those two marks, for loss due to evaporation. I check the sg every few weeks, and it's usually 1.025 - 1.026 . . . so I think I'm okay with my salinity.

Tks for your reply.

 

[cracker]

Welcome Ice Dog, I can't think of anything to add. If you take out 5gals You should be able to add 5 gls back ! That's physics ! I'm not sure what Your LFS was talking about ?
One question, You are turning off the return while doing water changes ?

 

[Icedog]

Too funny and too true. Still lol

We welcome you to the community. You are on point. If you take out 5 and put in 4 = empty tank eventually. (Peace river not only one can do math)

It can throw you off a bit if you fill up one before the other. What I usually do is turn off my pumps before the change. Water drains back into the sump. Then I do the change in DT. I add water to the DT to about the normal level. I stop filling once near top level and turn on the pumps. The sump will pump the wate in the tank. If you are even then all set. If the sump water level after it is running then it is high and drain a bit out. Usually when I fill I leave a few gallons short when I fill. Then I hit the pump on. All the water drains from the sump and The pump starts shooting bubbles and I add more to the sump until I get the right level

And WELCOME

Thanks for your suggestions! And I think you may have hit on something here - fill up the DT with fresh salt water first, restart the pump, and then empty the rest of the salt water into the sump. I'll definitely try that next time!

 

[Icedog]

Welcome Ice Dog, I can't think of anything to add. If you take out 5gals You should be able to add 5 gls back ! That's physics ! I'm not sure what Your LFS was talking about ?
One question, You are turning off the return while doing water changes ?

Yes, I am. But I have been turning off the protein skimmer - should I?

 

[Icedog]

Yes, I am. But I have been turning off the protein skimmer - should I?

Sorry, I meant to say I have not been turning off the protein skimmer. Should I turn that off also?

 

[cracker]

I turn off my skimmer when doing water changes. I'd say it's worth a try. I can't understand why the water level rises though . It is easily taken care of . Just take some water out until it's at your mark then turn the skimmer back on. That's what I would do. Good luck & let us know how it works out.

 

[Peace River]

I am usually pretty good with maths (especially when I don't have to take off my shoes), but I used a phone-a-friend just to make sure that 4 doesn't equal 5.

He assured me I'm right. ;Happy

 

[Icedog]

I turn off my skimmer when doing water changes. I'd say it's worth a try. I can't understand why the water level rises though . It is easily taken care of . Just take some water out until it's at your mark then turn the skimmer back on. That's what I would do. Good luck & let us know how it works out.

Thanks again, Cracker! Yeah, that's what I've been doing - taking out water from the tank until the sump is at the appropriate level. But I just hated "wasting" the new salt water by taking it some out of the tank right after I had added it in! And I figured it must be something I'm doing wrong - thanks to all of the people on this this thread, I think I'm headed in the right direction to solve this issue.

Again, thanks to everyone here for their suggestions - will keep you updated on what happens next!

 

[KorD]

I use a hunk of painters tape on my sump. Turn off the pumps and such, give it 5 min to fully settle and then remove the water I want out.. I then just fill the sump back up to the tape line and call it good.
Once the tank has run for a few min I check to see if my second tape line is where the water in the sump should be.. if I need more I add more