Lowering Salinity from 36.59 to 35 / Help Please

[AndrewBrusca]

Hi Everyone,

I have what appears to be a very happy 225 gallon mixed reef tank that is approaching 1 year and 3 months.

Acros are growing and presumably happy. However to my surprise, the ICP test showed that my salt was too high at 36.59. Other parameters were fine outside of Manganese and Iodine.

For whatever reason I haven't recalibrated my Hanna salinity tester in 6+ months (odd noob mistake, lesson learned). So now i'm looking to get my salinity down to 3.5. I also calibrated my hannah salinity tester and it showed 3.6 after only showing me 3.5 for months, oops.

Is the best way to do this, removing like 5 gallons of tank water per week and replacing it with 5 gallons of non salt RODI?

Alternatively, I was considering adjusting my WC water to 34 salinity and doing my typical 25 / 30 gallon weekly water change and adjusting slowly that way.

I want to ensure I don't shock any coral or tank inhabitants, is there any general direction on the best way to get my salinity down?

Thanks for any feedback!

Best,
Andrew

 

[Fish Fan]

You can safely lower salinity much more rapidly than you should raise it I'd probably go right to 35 ppm, but if you wanted to do it more slowly I don't thing there's harm considering your tank is doing well at the elevated salinity currently.

I hope that helps!

 

[AndrewBrusca]

You can safely lower salinity much more rapidly than you should raise it I'd probably go right to 35 ppm, but if you wanted to do it more slowly I don't thing there's harm considering your tank is doing well at the elevated salinity currently.

I hope that helps!

How would one go directly to 35 ppm? I'm assuming that means do the calculation and don't over think doing it slowly over time?

Random, but I was also thinking I could remove a gallon per day via gallon jug container. And simply let the ATO replace it...

Also, from the 10 minutes of research i've done on lowering salinity. I do understand that lowering it is less offensive to acclimated coral than raising it. Thank you for confirming that. :)

 

[Fish Fan]

How would one go directly to 35 ppm? I'm assuming that means do the calculation and don't over think doing it slowly over time?

Random, but I was also thinking I could remove a gallon per day via gallon jug container. And simply let the ATO replace it...

Also, from the 10 minutes of research i've done on lowering salinity. I do understand that lowering it is less offensive to acclimated coral than raising it. Thank you for confirming that. :)

Honestly, if you have an ATO, that's exactly how I would personally do this. Remove a little water and let the ATO catch it up, then repeat

 

[AndrewBrusca]

Honestly, if you have an ATO, that's exactly how I would personally do this. Remove a little water and let the ATO catch it up, then repeat

Perfect, thank you. I took about 2 cups out earlier prior to even having a plan lol. I’m gonna plan to fill the ato reservoir more regularly and test. Ty

 

[KStatefan]

How would one go directly to 35 ppm? I'm assuming that means do the calculation and don't over think doing it slowly over time?

Random, but I was also thinking I could remove a gallon per day via gallon jug container. And simply let the ATO replace it...

Also, from the 10 minutes of research i've done on lowering salinity. I do understand that lowering it is less offensive to acclimated coral than raising it. Thank you for confirming that. :)

That is how I would do it.

Here are the calculations

 

[AndrewBrusca]

That is how I would do it.

Here are the calculations

I saw this calculator shared on another lower salinity thread but didnt successfully use it lol. Thank you for sharing the calculation.

Unnecessary but i intend to remove a gallon a day or every other day and allowing the ATO to do the rest. Thanks all, this forum makes managing a reef so much more stable

 

[Bruttall]

Hmm, I hover around the 1.024 to 1.025 range in my 300g tank, when the range drops blow 1.024 I just take a gallon of water out, add 2 cups salt to it, mix well, pour back into the sump. Retest salinity in 2 hrs. rinse repeat as needed to raise to desired level.

To lower Salinity I remove a gallon and add a gallon RO/DI, retest in 2 hrs, Rinse repeat. This is one reason why I love having a large volume system, the changes are way more gradual than you would experience in a 30g tank. So adjusting is pretty easy, just takes a little patience.

why 2hr interval? My tank turns over somewhere between 8 and 12 times per hour, so that gives ample time for the water to mix. I could shorten that time frame I suppose, but this works for me.

 

[mmorrison55]

Do you make your own saltwater? And if so, I assume you have an rodi holding tank nearby?

As was shared via the hamza reef calculator, you need to pull out 10 gallons of sump water and add 10 gallons of rodi to get your salinity @35 ppt.

In most standard sumps, that would be like draining your return pump section, may be only 1/2.

When I do regular weekly water changes, I use the return pump section for a quick idea of how much water I want to change. So it’s a quick drain and replace. No thinking required.

In your case, instead of replacing with clean new saltwater, you will replace with clean fresh rodi.

As others have said replacing 10 gallons in one go would not harm your 220 system inhabitants.

 

[AndrewBrusca]

Do you make your own saltwater? And if so, I assume you have an rodi holding tank nearby?

As was shared via the hamza reef calculator, you need to pull out 10 gallons of sump water and add 10 gallons of rodi to get your salinity @35 ppt.

In most standard sumps, that would be like draining your return pump section, may be only 1/2.

When I do regular weekly water changes, I use the return pump section for a quick idea of how much water I want to change. So it’s a quick drain and replace. No thinking required.

In your case, instead of replacing with clean new saltwater, you will replace with clean fresh rodi.

As others have said replacing 10 gallons in one go would not harm your 220 system inhabitants.

Okay great, thank you everyone!

 

[exnisstech]

the ICP test showed that my salt was too high at 36.59. Other parameters were fine outside of Manganese and Iodine.

For whatever reason I haven't recalibrated my Hanna salinity tester in 6+

I've had two of the Hanna salinty testers and they both read 0.002 low when calibrated using Hanna's calibration fluid.

 

[OrionN]

I would remove at least 2 gal per day at the minimum and replace it with RO water. In a 220 gal system, this is only 1 percent decrease which is about from 36.6 to 36.25 or so. Just measure and follow as you do it. This will have no adverse impact on your animals decrease it this slow. If you want you can decrease it much quicker.

 

[Pistondog]

Hi Everyone,

I have what appears to be a very happy 225 gallon mixed reef tank that is approaching 1 year and 3 months.

Acros are growing and presumably happy. However to my surprise, the ICP test showed that my salt was too high at 36.59. Other parameters were fine outside of Manganese and Iodine.

For whatever reason I haven't recalibrated my Hanna salinity tester in 6+ months (odd noob mistake, lesson learned). So now i'm looking to get my salinity down to 3.5. I also calibrated my hannah salinity tester and it showed 3.6 after only showing me 3.5 for months, oops.

Is the best way to do this, removing like 5 gallons of tank water per week and replacing it with 5 gallons of non salt RODI?

Alternatively, I was considering adjusting my WC water to 34 salinity and doing my typical 25 / 30 gallon weekly water change and adjusting slowly that way.

I want to ensure I don't shock any coral or tank inhabitants, is there any general direction on the best way to get my salinity down?

Thanks for any feedback!

Best,
Andrew

Use randys diy salt calibration fluid to check your tester.
Post in thread 'Salinity - what to trust?' https://www.reef2reef.com/threads/salinity-what-to-trust.1125964/post-13826474

 

[dschuffert]

Similar to what others have stated, I would calculate how much salt water to remove and then replace with fresh water. My system is 242 gallons. I use a 3 part dosing system which is salt based and can easily get away from me. I have rapidly dropped from 39 ppt down to 35 ppt without any issues that I saw to my fish and corals.

 

[mmorrison55]

If you don’t already have this site, it’s a good one to link to your url bar or at least make a favorite.

https://www.hamzasreef.com/Contents/Calculators/ResultingSalinity.php

I use it mostly for how much salt I need to add to my RODI water to make 34/35 ppt but it has a lot of other useful calculators that can be used for our hobby.

 

[Randy Holmes-Farley Verified Community Expert]

I've had two of the Hanna salinty testers and they both read 0.002 low when calibrated using Hanna's calibration fluid.

What did you test them with to see they were low?

 

[sjfishguy]

If everything is going great why do you want to drop it? Lots of people run thier salinity there.

 

[exnisstech]

What did you test them with to see they were low?

I compared them to two refractometers calibrated with your DIY fluid and also a TM hydrometer.
If I calibrate the Hanna tester with SW at 1.026 they'll read 1.026. If I calibrate with Hannas fluid they will read 1.024 when testing water confirmed to be 1.026 .

 

[Randy Holmes-Farley Verified Community Expert]

I compared them to two refractometers calibrated with your DIY fluid and also a TM hydrometer.
If I calibrate the Hanna tester with SW at 1.026 they'll read 1.026. If I calibrate with Hannas fluid they will read 1.024 when testing water confirmed to be 1.026 .

Ok, perhaps the Hanna fluid is faulty.

 

[AndrewBrusca]

If everything is going great why do you want to drop it? Lots of people run thier salinity there.

I generally like keeping salinity in the middle of the recommended range at 1.025.

Which in theory if over months, salinity drifts high or low. I have more room on both sides of the range before i fall out of range.

Ive been removing one gallon per day and replacing with fresh for the sake of gradual change.

Random question and i assume this is not a legitimate concern based on all the replies so far. But if i replace too much salt with fresh water all at once. Wouldnt that drop something like alkalinity by several points?