Low calcium and magnesium readings

[Trooper182]

My 75gal fish only tank has been running with fish now for almost a month and everything in the tank is doing fine. I got some aquaforest test kits today to test magnesium and calcium. My other testers are Hanna and Salifert testers. The readings I got showed low levels for Ma and Ca. My salinity is 1.023 (not pictured) and I use instant ocean salt. My last water change was this past Saturday and I did a 20% change. Should I really worry about these low levels right now? Eventually I would like to add some corals.

 

[firechild]

Neither of those readings are critically low. It might be worth checking the levels of some freshly mixed salt to get a baseline for what you will need to do moving forward. If the salt is mixing at a low level, it might be worth considering a switch in brands. I wouldn't worry too much about trying to get this up until closer to the time you are ready to add corals, otherwise you are just paying to dose chemicals that will just go out with water changes. Increasing your SG to 1.027 will also increase the levels of those elements so it might not be too far away from where it needs to be.

 

[Trooper182]

Neither of those readings are critically low. It might be worth checking the levels of some freshly mixed salt to get a baseline for what you will need to do moving forward. If the salt is mixing at a low level, it might be worth considering a switch in brands. I wouldn't worry too much about trying to get this up until closer to the time you are ready to add corals, otherwise you are just paying to dose chemicals that will just go out with water changes. Increasing your SG to 1.027 will also increase the levels of those elements so it might not be too far away from where it needs to be.

Thanks, if I raise my SG, how long of a period should I do it over? I know it needs to be raised slowly.

 

[firechild]

With just fish in your tank, I wouldn't be too concerned about the increase. Start mixing your new water to 1.027 and with each 20% water change, you will creep up on the mark. How soon do you plan on adding corals?

 

[Trooper182]

With just fish in your tank, I wouldn't be too concerned about the increase. Start mixing your new water to 1.027 and with each 20% water change, you will creep up on the mark. How soon do you plan on adding corals?

I probably won't start adding anything until around Nov-dec. The tank is still young and kinda want to get some time and coralline growth first.

 

[Reefer Matt Verified Media Partner]

It is okay for now as a fowlr tank. I recommend switching to the reef crystals a few months before adding coral. Instant ocean doesn't have enough cal and mag in it for some coral.

 

[firechild]

If you just do water changes with 1.027, your salinity will rise like this. It will be within range before long and you can bump it up at some point before you add corals if necessary.

 

[Pachiman]

I probably won't start adding anything until around Nov-dec. The tank is still young and kinda want to get some time and coralline growth first.

It is a bit hard to grow coralline on a new tank. I added my first coral before my first fish, some GSP and zoanthids which are still growing to this day.

No need to wait until dec/nov for some easy soft corals you can enjoy them now. Be sure to get proper lightning like a radeon or a prime light, and start really slow with the cycle 2-3 hours a day otherwise its going to be a algae-only tank.

For softies calcium doesn't matter too much they are too forgiving.

For the low levels of calcium/magnesium sometimes its bad luck with the salt batch. I had really low levels with aquaforest reef salt, then switched to tropic marine and the values kept going up. I even had some LPS with 390 calcium, now it is 450 after dosing with seachem.

 

[Trooper182]

Right now I have two nicrew 150w led lights. I run them on a 3PM-930pm light schedule mainly blue light with little white mixed since the fish really don't need light and nobody is home to enjoy the tank until around 3 anyway. After this trip I have coming up I may start adding a few soft corals.

It is a bit hard to grow coralline on a new tank. I added my first coral before my first fish, some GSP and zoanthids which are still growing to this day.

No need to wait until dec/nov for some easy soft corals you can enjoy them now. Be sure to get proper lightning like a radeon or a prime light, and start really slow with the cycle 2-3 hours a day otherwise its going to be a algae-only tank.

For softies calcium doesn't matter too much they are too forgiving.

For the low levels of calcium/magnesium sometimes its bad luck with the salt batch. I had really low levels with aquaforest reef salt, then switched to tropic marine and the values kept going up. I even had some LPS with 390 calcium, now it is 450 after dosing with seachem.

 

[Pachiman]

Right now I have two nicrew 150w led lights. I run them on a 3PM-930pm light schedule mainly blue light with little white mixed since the fish really don't need light and nobody is home to enjoy the tank until around 3 anyway. After this trip I have coming up I may start adding a few soft corals.

Those are both good lights and a good schedule, for corals you will probably want at least 12 hours a day and it has to be in a slope kind of shape (starts really dim then goes up and finally down).

You have all your rock stacked together (no islands) so stay FAR AWAY from xenias/GSP because they grow like crazy. I recommend zoanthids or rhodactis, personal favourites of mine, or you can throw a sarcopython as well.

Be sure to feed your fish more often so you get more NO3 as those corals need some NO3 levels to thrive.

 

[Trooper182]

Those are both good lights and a good schedule, for corals you will probably want at least 12 hours a day and it has to be in a slope kind of shape (starts really dim then goes up and finally down).

You have all your rock stacked together (no islands) so stay FAR AWAY from xenias/GSP because they grow like crazy. I recommend zoanthids or rhodactis, personal favourites of mine, or you can throw a sarcopython as well.

Be sure to feed your fish more often so you get more NO3 as those corals need some NO3 levels to thrive.

Thanks. Yea I realized after making the rock formation I should have added some islands. I still have room to add some small islands so may break some dry rock this weekend and place a few in there. This is another light schedule I made that I was thinking of trying. I kinds want to mimic a more natural light schedule but without using much white light until I do add choral. As I understand it, more white light can lead to unwanted algae growth thin the tank?

 

[Pachiman]

Thanks. Yea I realized after making the rock formation I should have added some islands. I still have room to add some small islands so may break some dry rock this weekend and place a few in there. This is another light schedule I made that I was thinking of trying. I kinds want to mimic a more natural light schedule but without using much white light until I do add choral. As I understand it, more white light can lead to unwanted algae growth thin the tank?

No, not really. With those levels you won't have any issues, but try to make it a bit brighter for corals. I have my lights at 100% blue 90% white and 0 algae but I started at 30% first month, 40% 2nd month, etc. The biggest culprit of algae is not light, but nutrient imbalance, extreme levels of nitrate, high phosphate, etc.

And algae is actually pretty good if it is manageable, I think of it as food for all my invertebrates than a plague on the tank. When it goes out of control because of nutrients or a lot of light is the issue.

 

[nereefpat]

A lot of posts here. First, there is nothing wrong with Instant Ocean. Lots of reefs run on regular IO. Also, for fish only, I wouldn't sweat Ca or Mg too much.

The salinity is about 10% low. If you top off with saltwater until salinity is 35 ppt (or 1.026 sg), Ca and Mg will increase 10%. I would just start there. No need to change water, just top off with saltwater.