Water parameters after first water change

[Gruca]

So I just did my first water change after setting up the tank and letting it cycle. Using Tropic Marin Pro Reef salt. I mixed 35g of saltwater at 1.023 salinity. Before the water change my alk was 9.5, calcium was around 400 and magnesium was about 1150. I had been removing saltwater and replacing with freshwater to get the salinity down after adding rocks and that’s where the parameters ended up.

Today I did the water change and my parameters went down to 8.09, calcium to 377, and magnesium to 1078. I’m confused as to why adding saltwater decreased these so much.

 

[fishywishy]

Why are you lowering your salinity? 1.023 was fine. The reason everything dropped is because the freshwater you added diluted the parameters. Just do a water change and they should return to normal.

That said, it’s still a too early to be adding corals that require these stable parameters anyway.

 

[Gruca]

Salinity jumped to 1.032 after adding in my rock work (I did rinse it), so I was lowering it down. After that, my parameters were at the first amounts I mentioned. Then, after doing the 25% water change with saltwater, the parameters dropped even further. I get it’s not a huge deal without having coral yet, however when I do get coral, this would be an issue. That’s why I am asking, it just didnt make sense, that I am aware of, for it to decrease.

 

[Gumbies R Us]

Are you sure you are mixing the salt properly and matching the salinity to your tank? It shouldn’t be dropping your parameters by that much.

 

[Mr. Mojo Rising]

What salinity tester are you using? Salinity should not increase from adding rocks, and that is a really big jump, it doesn't seem likely to me.

 

[p1u5h13r4m24]

What salinity tester are you using? Salinity should not increase from adding rocks, and that is a really big jump, it doesn't seem likely to me.

Ya I’m guessing this is a salinity tester error as well. Unless those rocks are made of salt; I can’t see why salinity would increase that much.
How many total gallons is this system?

 

[Gruca]

About 140g total, 120g display. Using this refractometer to test salinity.

 

[p1u5h13r4m24]

Are you sure it’s calibrated ? Use r/o water n make sure it reads 0

 

[Gruca]

For some clarity, the salinity was about 1.028 before adding the rocks, it jumped to 1.032, then Igor it down to 1.023 and that is when I tested parameters.

 

[p1u5h13r4m24]

For some clarity, the salinity was about 1.028 before adding the rocks, it jumped to 1.032, then Igor it down to 1.023 and that is when I tested parameters.

Ok I think I get what you’re saying. It was high than u added rock and it was higher(not sure why) than you lowered it to 1.023 (low salinity is why u have low parameters ur salt bucket will tell u what ur parameters are at at which salinity/ higher salinity higher parameters).
So if you want to bring ur parameters where they need to be? Than bring ur salinity to where it needs to be 1.026 than retest your parameters :)

 

[p1u5h13r4m24]

And by the way all these water changes on a freshly cycled tank could 0 nutrients and throw off your cycle causing it to recycle.

 

[ColorMeGone]

Not sure if those should be calibrated with RO water. I would get some cal. solution to set up your refractometer. I have the same one and it works well. Get your water to 1.026 and let your tank do its thing. Just do top offs with RODI water to keep stable.

 

[mjszos]

Salinity jumped after adding rocks?

Where did you get your rock? Even if it were pre-cycled live rock, it shouldn't have been able to increase your salinity that drastically I don't think.

Can you take a water sample to an LFS to verify your numbers? What calibration solution are you using for your refractometer?

 

[stE26wy14]

lowering salinity means less salt, less salt means less nutrients from that salt, if u look at your salt dosing instruction sheet, it gives u all the parameters at different salinities

 

[p1u5h13r4m24]

Not sure if those should be calibrated with RO water. I would get some cal. solution to set up your refractometer. I have the same one and it works well. Get your water to 1.026 and let your tank do its thing. Just do top offs with RODI water to keep stable.

Yes refractometers are to be calibrated to 0 with deionized water. It will say it in the instruction booklet it came with.

 

[ColorMeGone]

Yes refractometers are to be calibrated to 0 with deionized water. It will say it in the instruction booklet it came with.

I use a cal. solution, and it works perfectly. I just now tested it with some RODI water, and it does calibrate to 0 so mine works both ways, sorry for the bad info.:oops:

 

[BryanM]

1.023 salinity is on the low side.

I suspect testing errors for those calc and mag numbers. Those are way too low, especially in a new tank, freshly mixed salt water, unless you're somehow mixing it incorrectly.

I'd take some water to the LFS and ask them to test it.

 

[p1u5h13r4m24]

Not sure if those should be calibrated with RO water. I would get some cal. solution to set up your refractometer. I have the same one and it works well. Get your water to 1.026 and let your tank do its thing. Just do top offs with RODI water to keep stable.

So the manual they come with says to use r/o however Randy has a thread saying we should use calibration solution. So I’m gonna have to get some as well

 

[Randy Holmes-Farley Verified Community Expert]

So the manual they come with says to use r/o however Randy has a thread saying we should use calibration solution. So I’m gonna have to get some as well

Which device?

Some/most are designed for brine, not seawater, and even if perfectly made and perfectly calibrated per manufacturer directions, will necessarily be inaccurate to some extent.

Using an accurate seawater fluid eliminates all these concerns.

 

[p1u5h13r4m24]

Which device?

Some/most are designed for brine, not seawater, and even if perfectly made and perfectly calibrated per manufacturer directions, will necessarily be inaccurate to some extent.

Using an accurate seawater fluid eliminates all these concerns.

Hey! This is directly from the Red Sea refractometer calibration instructions
Calibration:


Alignment should always be carried out with the


instrument at 22-25°C. Allow the refractometer to stand at


this temperature for 30 minutes before alignment.


1. Remove the cover from the alignment screw.


2. Place a sample of DI water on the glass prism and check


the salinity reading as directed above.


3. If the reading is not exactly on the zero ppt mark on the


scale, adjust the position of the reading by rotating the


alignment screw with the screwdriver provided until the


reading is zero ppt.


4. Replace the cover from the alignment screw.