What is your experience with magnesium?

kng

kng

New member
I have had a reef tank for about 4 years now (mostly nanos) and have never messed with magnesium. Recently (last 3-6 months) on my 58 I have noticed the following conditions:

1) Loss of color (mostly in SPS) of corals
2) Loss of purple color of coraline algae
3) Slow hard coral growth

Here are my average tank parameters:

Temp: 82
Salinity: 1.024
Calcium: 360
Alkalinity: 7 DKH
Ph: 8.2
Ammonia, Nitrite, Nitrate: 0

Here are other conditions:

-250W DE Phoenix 14K bulb
-36" 39W T-5 Actinic Supplement
-20 Long sump with Euroreef ES5-2 skimmer and Phosban Reactor
-I feel like I have descent flow.
-I dose Kent Part A in the morning, Part B at night, and drip 2L of Kalk every night.
-I feed flake every night, and feed frozen brine and mysis shrimp with Golden Pearls once a week. (Not a heavy feeder).
-I use IO salt.

I tested my mg tonight for the first time, and it is 1050.

What are your thoughts/experiences?

How can I raise this (I assume dosing, but what brand)?

Do you think this level relates to conditions 1, 2, or 3?

Do you think my Ca would raise a little if I raised mg?

Sorry for the lenghty post, but I was scared Harry was going to get on us again for slow activity here lately! :lol: :rollface: :lolspin:

Thanks!
 
That would explain why your cal is low if you are doseing and can not bring it up.

1050ppm is pretty low, I dose Mag. the reason is most salt mix around 1100ppm And I like mine about 1250ppm-1400ppm. Natural sea water is ~1290ppm.

I think you have a 58 gallon. so this is for 55 gallons of water.

I would dose slowly I would bring it to 1290ppm. If you use epsom salt it will take about 18.3 oz to bring it to ~1290ppm. Dissolve it in RO / DI water and add it to a high flow area Don't dose it all at one time brake it up in to ~2 oz doses.

If you don't want to use epsom salt becasue of the sulphates you could use MAGFLAKE 15.4 oz would be the dose to bring your mag to ~1290ppm. You can get this from Buck Eye Field supply here on RC. Dissolve it in RO / DI water and add it to a high flow area Don't dose it all at one time brake it up in to 1.5 oz doses.


Another option is Kent tech m you will need 25.4 oz of this to bring your mag to 1290ppm. Don't dose it all at one time brake it up in to about 3 oz doses.


As you dose this and doses you sould be able to rasie your dkh and your cal.

Philip
 
Kyle,
Low mag can result in more rapid depletion/percipitation of calcium and alkalinity. Your calc/alk numbers appear to be OK, but on the low end. Is this where you've usually kept them?
If they are normally higher, low mag could be the reason. And so, indirectly, low mag could be contributing to 1, 2 & 3,
Of course other factors could be a build up of phosphates, old light bulbs, degenerating sand bed, etc.

Personally, I've had a really hard time keeping calc/alk/mag up in my 40g system, and it is also suffering from poor coral coloration and anemic coraline growth -- so I may not be the best one to give advice on this.

You can raise Mag by using Epsom salts that you can find in any Pharmacy, however if you do so routinely without water changes, you may create a buildup of sulphates. A better option is using MagFlake, which is hard to find locally, but Beaslbob was giving it away at the last NARC meeting. I've used both, as well as OTC supplements.
It takes a huge amount of either one of these supplements, or the ready made OTC supplements, to raise Mag significantly. There's a great Reef Calculator that you can use for determining how much you need (it also does computations for calc and alk, using various additives).
Randy Holmes Farley's article gives a pretty thorough explanation of the function of Mag in a reef as well as some DIY recipes at the bottom of the article.
HTH,
Mariner
 
8Ball told me recently that his SPS's turned very pale as well, and that he thought that it was caused by him adding a phosban reactor with the full dose of phosban. His blue tort went to baby blue color from the deep purplish blue. He also aggressively skim his tanks, too. Your corals may be phosphate limited and cannot take up other nutrients. The color loss may well be related to the lack of nutrients.

As for Magnesium chloride, I can share some with you since beaslbob gave me a lot of it. When I let my magnesium go too low, I did not experience any of my SPS's turning pale, but then again I am a heavy "coral" feeder (live rotifers everyday plus some oyster eggs and golden pearls added periodically.) The low magnesium and calcium seems to explains the slow coralline growth, although I heard that the coralline growth slows down as tanks matures.

How is your sand bed? Is it turning hard? I suspect that your calcium is precipitating on various surfaces without having magnesium to interfere with the precipitation. How are your heater strip and pumps? Are they getting a lot of calcium build up? If corals are not using calcium to grow even though you are adding a lot of it through daily 2 part supplement and nightly kalkwasser additions, calcium must be going somewhere....

Tomoko
 
Philip,

I'm going to try the Kent Tech M.


Mariner,

The Alk/Ca is where it's at because it's as high as I can get it.

Also forgot to mention that I change 5 gallons of water a week.

I change my bulbs every 12 months, and they are due in February.

Tomoko,

I've had the phosban reactor running the entire time the tanks been set up with Phosguard. I don't know how much you're supposed to put in, but I know I put less, because I heard the same thing. There's probably only 1 cup in the reactor, and I change and alternate it every month with carbon. That is a good place to look for getting color back. I know the tri-color acro I got from you looks horrible compared to when I first got it. Maybe after I see how this mg does, I can go to carbon only in the reactor for a few months. (Feeding more might help too).

I really don't have a lot of calcium precipitate. I did have the sand bed get hard in one spot once, and I loosened it and it's been OK since.

All,

Thanks for the ideas, I really think this is going to help my tank a lot! I'll let you know how it turns out.
 
My phosban is lasting pretty long. I wonder if you are adding too much and changing too frequently.

I put in about 100 grams (2/3 of the smaller container) for my 120G tank and I replace it only when I get impatient (that's like once every 5 months or so since phosphate tests always read zero in my 120.)

Tomoko
 
Tomoko for what it is worth I have seen the lighitng that you talk of with the use of phosban, I think it is a reaction that happens in the water, because I have seen it happen with PO4 above .15ppm . I have not seen it with vodka dosing. with the PO4 around .01ppm
 
I suppose you are still dosing vodka. Is it working well for you?

I stopped it when I started losing my cardinals. My phosphate is still reading zero with my Salifert test kit. Are you using Hach's or Lamott test kit or a colorimeter to be able to measure PO4 so precisely?

The color of my green milli got much brighter with vodka dosing in the first week or two. Phosphate test results were always zero although my nitrate results fluctuated between .2 to .5 range with vodka dosing. I never could bring nitrate down to zero and my macroalgae in the fuge were languishing in the lean water (probably PO4 limited.) The coral never lost its bright color even after I stopped dosing vodka, though. Funny, isn't it?

I was also using prodibio with vodka and I cannot really tell which one caused the fish loss. I first thought that my two huge emerald crabs were eating them, but when I stopped dosing both vodka and prodibio, I stopped losing my cardinals altogether.

Sorry, Kyle. I did not mean to hijack this thread to talk about vodka.

Tomoko
 
I am using a colorimeter from hanna. I am still using vodka on a 30 on 30 days off. Odd that you were losing cardnial fish. The only draw back I have seen a few LPS seem to act funny.
 
Hmm, every tanks are different, they say... I read a number of fish loss reports with vodka but none about coral acting funny. However, now that you mentioned it, I recall that my candy cane (which was doing really well before) was acting funny, too.

Tomoko
 
I cant dose vodka anymore!

I cant dose vodka anymore!

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Forgot to mention that my photoperiod is as follows:

9 hours MH
10 hours actinic

How does this compare to everyone else's? There is some discusion in the SPS forum that too long of a photoperiod will add to color loss.
 
I have my MH on for 8 hours. I used to have it on for 9 hours, but because of the heat issue in the summer time I cut it back to 8. I have not noticed any difference in coral coloration, though.

Have you checked your freshly mixed IO salt parameters? I had a very puzzling time with a very slow growth and some tissue recession with some of my acros this summer. After I switched my salt from IO to Seachem's Reef Salt this autumn, I started seeing a great improvement (after two or so water changes with the new salt)!! The recession stopped and tissue grew back. The color of the corals that were suffering improved tremendously as well. I understand that some people have had issues with IO salt (bad batches) including John Newby.

Tomoko
 
My lights use to stay on for 10 hours but I cut them back also.. My 180 has 2x 250 and 1x400.. The 250s are on 8 hours and the 400 is on for 7.. All my other lights are on for 8 hours. I've read several times that after 6 hours the corals dont really use the light.. Not sure how true that is.. But I haven't knoticed any problems at all cutting back from 10 to 8.. Utility bill went down a lil though :)

I also agree with Tomoko about the Salt... I quit using IO over a year ago.. I dont know if I had a bad batch or what. But every time I did a water change with IO my tank got out of wack one way or another.. I use reef crystals now. Same company but its suppose to be alot better for reefs then standard IO.. It seems to work better to me.. I've also heard alot of people really like Seachems reef salt too. I'm thinking about giving it a try since its about the same price as Reefcrystals.

Will
 
I understand that a lot of plants and algae including zooxanthellae get saturated with light energy in less than 6 hours. The latest thing in planted aquarium is to use MH light for 4 to 6 hours for plants to photosynthesize and switch the lighting to PC's for the remainder of the light period mainly for our viewing. I recall reading on RC that some people are having a great success using MH for 4 hours only and using actinic bulbs for the remainder of the time. It saves on the power consumption, too.

Tomoko
 
4 hours straight, or would 1 on 2 off be better? and if the rest of the time is for 'our' pleasure, we would just need lights that gave us the color we appreciated the most?
 
I belive that a extreme amount of light for a 6 hour photo period with lots of blue gives the best color, but for growth a yellowish 12 hour is better.
 
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