No additives just water changes

[WhiteTang]

Hi everyone!

I have a 16g tank with 5 SPS, 5 LPS and a couple zoas.
I do weekly 20% water changes to be sure that trace elements and Ca, Mg & Kh are in check.
My problem is my high Mg. I use Tropic Marin bio-active salt and it looks like my Mg is going up all the time.
I have never ever dosed anything but carbonates because of "low" Kh (7dKH).
I keep my salinity at 1.024,5 and temperature is always 25°C.
Since all my frags are small i think I could get away with 20% weekly water changes without adding anything.
The problem I am having with my Mg, which used to be around 1400 a couple months ago, and now is around 1600 makes me think I probably have a bad batch of salt.
Im looking into buying a new bucket and was wondering which salt you would recommend? Is there any salt out there that would give me the optimal levels of KH, CA, MG etc?

 

[Eric Boerner]

Actually... You can fix all of your problems by adding two part solution. Your low dKH will increase with the Ca, while at the same time, your Mg will decrease as your corals are sucking up more calcium carbonate.

Right now your low dKH and high Mg is limiting calcium carbonate, which is not allowing your corals to consume it.

 

[WhiteTang]

But aren't the two-part additives adding Mg as well? I mean one will raise my KH while the other will add calcium AND Mg...(among other things).
Unless there is a two-part system that raises ONLY KH and the other ONLY Ca?

 

[Jettareefer]

I've tried what your currently doing water changes and dosing alk, needless to say after all my corals start growing like crazy I have about 25 Sps colonys in a 60 gallon I couldn't keep MG and Calcium up. That's with 20 gallon water changes bi-weekly. My mag was as low as 1000 I know this isn't your particular problem. Now dosing the 3 core trace elements things are on point with smaller water changes. I do agree with the post above dosing would be better from a growth perspective and overal your corals will be happier. Also you could lower your water changes this the mag will come down as you add buffer for calcium and alk.If you want to go with a salt that has a lower mag level I personally use regular coralife salt with great colors the mags 1350 which Is a sweet spot. Reef crystals also isn't a bad option as well. I've done some reading on salt a lot of reefer dislike tropic Marin for its inconsistency and weird level of certain things. Hope this helps!

 

[Peter Eichler]

But aren't the two-part additives adding Mg as well? I mean one will raise my KH while the other will add calcium AND Mg...(among other things).
Unless there is a two-part system that raises ONLY KH and the other ONLY Ca?

No, two parts are two parts, the calcium part and the alkalinity part. Magnesium needs to be added independently...

 

[WhiteTang]

No, two parts are two parts, the calcium part and the alkalinity part. Magnesium needs to be added independently...

Thanks for the reply.
Could you suggest a two part dosing system?
Red sea Max? Or Elos? Seachem?

 

[CommsTech]

Randys recipe is the most cost effective and works great.

 

[MisterP]

For a 16 gallon tank I would just buy ESV. It is very high quality and with that size tank will last a long time.

Sure, the bulk 2 part recipes from BRS are cheaper but we're talking about dosing 5-10 mL / day, which is nothing. That bulk 2 part will last YEARS. Save some hassle with mixing and buy pre-mixed.

 

[Wazzel]

No, two parts are two parts, the calcium part and the alkalinity part. Magnesium needs to be added independently...

Depends on what system you use. Seachem reef builder and reef advantage calcium have Mg and other trace elements in them. According to seachem they are in proportion to Ca and Alk. I have had good results with this system in the past and it is what I use now.

For a 16 g tank you are really not going to break the bank with any route. If it were me I would look to use a 2 part system that had trace elements in it.

 

[WhiteTang]

Thank you all for your input. After some research I think I will go with the RED SEA MAX, unfortunately we have no BRS here in europe so there are not A LOT of options....