Low Calcium in RO Water

[newreefer88]

Hi all, I recently purchased an Aquatic Life RO buddy with a DI cartridge so I could save a little money and stop purchasing so much from my lfs. I know that I do not have a state of the art RO system but I am a college student on a budget and I am new to the hobby, please save the 'judgy' comments.
My RO system is installed and working, I filled up a trash can with 12 gallons of water but I am having an issue with low calcium, my numbers are reading at 380, gravity 1.024, and dKH is 10.5. As for the water going through my RO system, it is well water and I live in a primarily slate area. I am not sure if that is the reason for low numbers, I have friends who do not live far from me but live around limestone and their calcium levels are fine.

I do not have a magnesium test yet but I ordered one and I'm waiting for it. I started dosing liquid calcium by Seachem Part 1 and 2 but should I be using the second since my dKH level is where it needs to be? Also, I dosed more than the amount needed and my numbers are not changing. I went and purchased liquid calcium (Coral Life Liquid Calcium) made by Kent. I added 1ml to start but no change, I am now up to 4ml and my numbers are still reading 380, how is this possible? I am using API test kit and have been using the same kit for about 2 months and never had an issue with the readings until now.

Any help would be appreciate! Thanks so much

 

[gbroadbridge]

Hi all, I recently purchased an Aquatic Life RO buddy with a DI cartridge so I could save a little money and stop purchasing so much from my lfs. I know that I do not have a state of the art RO system but I am a college student on a budget and I am new to the hobby, please save the 'judgy' comments.
My RO system is installed and working, I filled up a trash can with 12 gallons of water but I am having an issue with low calcium, my numbers are reading at 380, gravity 1.024, and dKH is 10.5. As for the water going through my RO system, it is well water and I live in a primarily slate area. I am not sure if that is the reason for low numbers, I have friends who do not live far from me but live around limestone and their calcium levels are fine.

I do not have a magnesium test yet but I ordered one and I'm waiting for it. I started dosing liquid calcium by Seachem Part 1 and 2 but should I be using the second since my dKH level is where it needs to be? Also, I dosed more than the amount needed and my numbers are not changing. I went and purchased liquid calcium (Coral Life Liquid Calcium) made by Kent. I added 1ml to start but no change, I am now up to 4ml and my numbers are still reading 380, how is this possible? I am using API test kit and have been using the same kit for about 2 months and never had an issue with the readings until now.

Any help would be appreciate! Thanks so much

You can't use most test kits on RO water as they are designed to test sea water.

Do you have a TDS meter? The output from the DI stage should have 0 (zero) TDS.

In any event, if this is a small new tank, you should not need to be dosing anything.

 

[newreefer88]

Thank you so much for your reply, I did not know that.

I do have a TDS meter, my number before RODI was 161, the number after was 2 so I know my system is doing what it needs to.

I know I am not the only one who uses an RODI system in the reef world so what test kit would I use to continue to monitor my calcium levels and other parameters?

 

[KStatefan]

You are not testing your RO water. If you bring your salinity up to 1.026 your calcium will also come up.

 

[snorklr]

RO water should have NO calcium...or anything else for that matter...that's the point of using it....once you add your salt mix that's where all the minerals come from

 

[newreefer88]

You are not testing your RO water. If you bring your salinity up to 1.026 your calcium will also come up.

I apologize I worded that incorrectly. I am testing my water after mixing it with Reef Crystals salt mix by Instant Ocean. I have attached the label that is on the back and at 1.023 it is saying I should have 405ppm calcium level and I am at 370ppm at 1.024.

I apologize if my post before was confusing. I am trying to figure out why my calcium is still low given the table I'm looking at. At this point even if I take it to 1.026 this means my calcium ppm would need to go from 370 to 455ppm?

Why did I not pay attention to chemistry in school?? hahaa

 

[Woodyman]

I apologize I worded that incorrectly. I am testing my water after mixing it with Reef Crystals salt mix by Instant Ocean. I have attached the label that is on the back and at 1.023 it is saying I should have 405ppm calcium level and I am at 370ppm at 1.024.

I apologize if my post before was confusing. I am trying to figure out why my calcium is still low given the table I'm looking at. At this point even if I take it to 1.026 this means my calcium ppm would need to go from 370 to 455ppm?

Why did I not pay attention to chemistry in school?? hahaa

What is your tanks current stocking?

Ca may not matter if it's 370 or 455 at the moment.

 

[newreefer88]

What is your tanks current stocking?

Ca may not matter if it's 370 or 455 at the moment.

That would be great haha!

Right now I have 2 branching hammers, 2 duncan, 1 nps gorgonian, 1 favia, 1 mushroom coral, and 1 goniopora. I am running a Waterbox Peninsula Mini

 

[gbroadbridge]

I apologize I worded that incorrectly. I am testing my water after mixing it with Reef Crystals salt mix by Instant Ocean. I have attached the label that is on the back and at 1.023 it is saying I should have 405ppm calcium level and I am at 370ppm at 1.024.

I apologize if my post before was confusing. I am trying to figure out why my calcium is still low given the table I'm looking at. At this point even if I take it to 1.026 this means my calcium ppm would need to go from 370 to 455ppm?

Why did I not pay attention to chemistry in school?? hahaa

Okay, an imporatant thing to remember is that hobby grade test kits are not very accurate. API test kits are less acurate than most others.

If you bring your salinity up to 1.026, which is where it should be if you plan to keep coral, the other elements would also increase.

If at 1.026 the API kit says 380, then it would be within the test kit error range. In any event it is not particularly important until you start to collect SPS corals. A Calcium level from 370-400 is fine for soft coral and LPS coral.

Oh, and the TDS out of a new RODI system should be zero. You may like to check it is installed correctly.

 

[Woodyman]

That would be great haha!

Right now I have 2 branching hammers, 2 duncan, 1 nps gorgonian, 1 favia, 1 mushroom coral, and 1 goniopora. I am running a Waterbox Peninsula Mini

Ok, so Ca is going to matter.

How old is this tank?

 

[newreefer88]

Okay, an imporatant thing to remember is that hobby grade test kits are not very accurate. API test kits are less acurate than most others.

If you bring your salinity up to 1.026, which is where it should be if you plan to keep coral, the other elements would also increase.

If at 1.026 the API kit says 380, then it would be within the test kit error range. In any event it is not particularly important until you start to collect SPS corals. A Calcium level from 370-400 is fine for soft coral and LPS coral.

Thank you so much! I will start searching for a more reliable test kit right away because I do not want to go through this again.

 

[newreefer88]

Ok, so Ca is going to matter.

How old is this tank?

It has been set up since December 21 and my parameters have been stable and Calcium at a steady 420-440, just changes a little from my water changes and not having an ATO yet. I use the ocean water I get from my local Petco but performing weekly water changes on a nano tank gets expensive hence purchasing my own RO system. Just wasn't sure why Ca wasn't anywhere close to my normal parameters but I just ordered a new test kit so we will check from there.

 

[Woodyman]

It has been set up since December 21 and my parameters have been stable and Calcium at a steady 420-440, just changes a little from my water changes and not having an ATO yet. I use the ocean water I get from my local Petco but performing weekly water changes on a nano tank gets expensive hence purchasing my own RO system. Just wasn't sure why Ca wasn't anywhere close to my normal parameters but I just ordered a new test kit so we will check from there.

First I'd suggest bumping up your salinity to 1.026.

But before you do that is your refractometer calibrated correctly? Did you use RO water or calibration solution when calibrating?

Your meter may be showing 1.024 now, but it may actually be 1.020

 

[newreefer88]

First I'd suggest bumping up your salinity to 1.026.

But before you do that is your refractometer calibrated correctly? Did you use RO water or calibration solution when calibrating?

Your meter may be showing 1.024 now, but it may actually be 1.020

Okay sounds good I will do that.

I did calibrate my refractometer using RO water but it's not worth double checking that at this point either!

 

[Woodyman]

Okay sounds good I will do that.

I did calibrate my refractometer using RO water but it's not worth double checking that at this point either!

Buy a calibration solution and use that as your verification/calibration going forward. Don't rely on the RO calibration.

 

[newreefer88]

Buy a calibration solution and use that as your verification/calibration going forward. Don't rely on the RO calibration.

Thank you for all of the information!

 

[Woodyman]

Thank you for all of the information!

Get that calibrated properly, bring your salinity up (slowly no more than 0.2 SpG/day). Then check your Ca again using a more reliable test kit.

 

[newreefer88]

Yes, I will definitely get all of that done and update!