How to lower Ca Mg and Kh?

[Ezra Blue]

Hey, my reef tank has been set up for almost a year now, and has been doing great, but for the past month my calcium and alkalinity have been very high. I then got a test kit for magnesium and that tested very high too! Every video or article I’ve read on how to lower either calcium or alkalinity has said that if one is high, the other will be low. This is not the case for my tank, so I did a quick 25% water change and nothing has changed all three are still high. I assumed this was alright since all three were high and balanced but today my octospawn look like they are “burned”. My pH is 8.4-.5 and other water parameters are good. Does anyone know what to do or how to lower these safely?

Thanks!

 

[Jekyl]

First thing I would do is verify your salinity. What are the actual levels of those parameters?

 

[Ezra Blue]

First thing I would do is verify your salinity. What are the actual levels of those parameters?

The salinity stays at 1.926-1.027, I have an automatic water top off system so I’m not too worried about that, my phosphates I like to keep at 1 as my tank is mostly softies, nitrates are at around .2- nothing, as well as ammonia levels. The calcium is at 550 alkalinity is at 14-15 and magnesium is at 1900-2000, all three of those I have heard to be to high.

 

[Jekyl]

The salinity stays at 1.926-1.027, I have an automatic water top off system so I’m not too worried about that, my phosphates I like to keep at 1 as my tank is mostly softies, nitrates are at around .2- nothing, as well as ammonia levels. The calcium is at 550 alkalinity is at 14-15 and magnesium is at 1900-2000, all three of those I have heard to be to high.

How are you measuring salinity? Is it calibrated regularly? I calibrate mine using calibration fluid before every use.

 

[Jekyl]

How are you measuring salinity? Is it calibrated regularly? I calibrate mine using calibration fluid before every use.

Look up your salt brand. It will tell you what levels it should be mixing to. I don't think any salt brand measures that high. Which points toward your salinity is high, thus increasing the other parameters.

 

[Ezra Blue]

Look up your salt brand. It will tell you what levels it should be mixing to. I don't think any salt brand measures that high. Which points toward your salinity is high, thus increasing the other parameters.

I use instant ocean reef crystals, and use the ATC refractometer for testing. The bucket the salt came in says that a salinity of 1.026 should be around 400 calcium and 3200 magnesium, (I made a mistake in my previous comment, my magnesium is higher than 3200). I just tested the salinity of the tank with two different refractometers and got 1.026-1.027, so I have no idea why the levels are high ‍. I may try to find another refractometer brand, or putting some more ROdI water in the tank to lower the salinity.

 

[Jekyl]

I use instant ocean reef crystals, and use the ATC refractometer for testing. The bucket the salt came in says that a salinity of 1.026 should be around 400 calcium and 3200 magnesium, (I made a mistake in my previous comment, my magnesium is higher than 3200). I just tested the salinity of the tank with two different refractometers and got 1.026-1.027, so I have no idea why the levels are high ‍. I may try to find another refractometer brand, or putting some more ROdI water in the tank to lower the salinity.

Do you have calibration liquid for them? I use the ATC and have to adjust it often.

 

[Ezra Blue]

Do you have calibration liquid for them? I use the ATC and have to adjust it often.

I do and just recalibrated them and the results are coming back the same, I make my own RO water, and just use that until the refractometer comes down to 0.

 

[Jekyl]

I'm stumped then. I'll bet @Randy Holmes-Farley knows though

 

[DivingTheWorld]

and 3200 magnesium, (I made a mistake in my previous comment, my magnesium is higher than 3200).

Is this a typo? 3200 Mag? Years ago when I tried high Mag for Bryopsis I only got to around 1850 and it killed off most of my snails. I'm surprised anything is alive at 3200. What are you using for test kits?

Something must be testing wrong...either Salinity, Cal, Mag, Alk, or everything. Have you tested a new batch of saltwater?

 

[Ezra Blue]

Is this a typo? 3200 Mag? Years ago when I tried high Mag for Bryopsis I only got to around 1850 and it killed off most of my snails. I'm surprised anything is alive at 3200. What are you using for test kits?

Something must be testing wrong...either Salinity, Cal, Mag, Alk, or everything. Have you tested a new batch of saltwater?

Maybe I’m thinking of something else for the mag, but I am currently using Red Sea and API, and like I said everything in the tank looks great except for a couple euphellyia so I’ll try differ t water and test again to see the results ‍. Thanks for responding!

 

[Randy Holmes-Farley Verified Community Expert]

Have you tested the new salt water? If it is high (by high salinity or anything else), then water changes cannot lower the values.

IMO, high salinity is most likely, but a batch of salt or a portion of a bucket low in sodium chloride might also give these values. And the values may be off.

 

[Ezra Blue]

Have you tested the new salt water? If it is high (by high salinity or anything else), then water changes cannot lower the values.

IMO, high salinity is most likely, but a batch of salt or a portion of a bucket low in sodium chloride might also give these values. And the values may be off.

I have tested the new water and my own tank again with another refractometer, and I’m getting the same results. I know it isn’t the salinity, there’s an automatic pump that senses when the water gets low (it evaporated) and the salinity goes up, so in seconds the pump turns on and puts some RO water in to balance it out. But nothing in my tank seems “wrong” a couple euphyllia are “burned” looking but other than that every other coral in there is exploding, and just within the last month I have at least five new heads on everything, the corals are so big they soon might not fit in my tank anymore . I just read the cal, alk, and mag at these high levels and got worried. Maybe I start spreading out the time in between water changes, maybe I’ve been doing them too close together for the nutrients to end up stacking up idk.

 

[Randy Holmes-Farley Verified Community Expert]

I have tested the new water and my own tank again with another refractometer, and I’m getting the same results. I know it isn’t the salinity, there’s an automatic pump that senses when the water gets low (it evaporated) and the salinity goes up, so in seconds the pump turns on and puts some RO water in to balance it out. But nothing in my tank seems “wrong” a couple euphyllia are “burned” looking but other than that every other coral in there is exploding, and just within the last month I have at least five new heads on everything, the corals are so big they soon might not fit in my tank anymore . I just read the cal, alk, and mag at these high levels and got worried. Maybe I start spreading out the time in between water changes, maybe I’ve been doing them too close together for the nutrients to end up stacking up idk.

I meant test the new salt water for alk, calcium, and magnesium.

 

[Ezra Blue]

I meant test the new salt water for alk, calcium, and magnesium.

I did and then I tested my frag tank and the cal alk and mag isn’t as high as my tank but is still very high at 1.026-7?

 

[Randy Holmes-Farley Verified Community Expert]

I did and then I tested my frag tank and the cal alk and mag isn’t as high as my tank but is still very high at 1.026-7?

Please list the exact values. What you are characterizing as very high is not necessarily a problem. For example, 550 ppm calcium is OK and some mixes start that high.

If it is equally high to the tank, then obviously water changes are not useful, whether the values are accurate or not.

Finally, API is not an especially reliable kit brand.

 

[Ezra Blue]

Please list the exact values. What you are characterizing as very high is not necessarily a problem. For example, 550 ppm calcium is OK and some mixes start that high.

Ok, the cal is around there and I have heard that that’s very high which is the only reason why I thought it was bad, the alk is 14-15, and mag I’ll test again today.

 

[Randy Holmes-Farley Verified Community Expert]

Every video or article I’ve read on how to lower either calcium or alkalinity has said that if one is high, the other will be low.

Thanks!

That isn't necessarily true, and you may want to look for better info sources.

Sadly, such comments do not correctly portray the issues, and such a misunderstanding has been propagated by ridiculous analogies like a bowl of marbles.

 

[Randy Holmes-Farley Verified Community Expert]

Ok, the cal is around there and I have heard that that’s very high which is the only reason why I thought it was bad, the alk is 14-15, and mag I’ll test again today.

Had you needed to dose any alkalinity in the past year?

If not, I'd use a lower alk mix on that tank. Reef Crystals starts quite high.

 

[Ezra Blue]

Had you needed to dose any alkalinity in the past year?

If not, I'd use a lower alk mix on that tank. Reef Crystals starts quite high.

Nope, I’ve never dosed anything at all, I’ll try and find another salt mix but this the reef crystals have been doing really well