Chemistry not quite right

[lrhorer]

My fish have all been doing very well for over two years. My corals have been a little less successful, but have been holding their own for the last several months. The greatest success has seemed to come from increasing the lighting drastically over my chato in the sump and dosing Magnesium. The soft corals are running wild - I have to prune them constantly to keep them from choking the tank. The LPS corals, however, are not growing very fast, if at all. I realize they will never grow as fast as the soft corals, but I think they could do better. All the chemistry parameters are well within normal limits except for the following:

1. Carbonate hardness. The hardness of my water continues to be higher than recommended. Most references I have seen suggest the dKH should be no higher than 11 (197ppm). Mine is typically 13 - 14 (233 - 251ppm).

2. Calcium. The Calcium level is below the recommended minimum for a reef tank, and Ca is absolutely essential for coral growth. Most references give the minimum recommended Ca level to be about 400 - 450ppm. Mine is about 380ppm.

The literature suggests a Ca level of 380 should be good enough, actually, but my concern is whatever I do to lower the alkalinity might further deplete the Calcium. Does anyone have a recommendation for slightly lowering the Alkalinity without negatively impacting the pH or Calcium levels? Better yet, raising Calcium and either raising pH a it or leaving it unchanged?

 

[ReefWreak]

Two part additives, only dosing the calcium part, will accomplish increasing calcium without impacting ph or alkalinity levels.

If calcium and alk are good (and STABLE), I'd recommend direct feeding of lps, and if that still doesn't work over time, you can always buy an ICP test like Triton, and see what it says.

Chemistry levels are #1, stability of those levels is #2, food is #3, and finally trace elements might be #4. This assumes you have appropriate lighting and don't have a disease or organism predating on your lps corals.

 

[FishAndPhysics]

What is the alk of the water you are using for water changes? What is your mag?

Are you dosing?

If I were you, I would make sure the alk of my water change water was below 12, mag was acceptable, and then dose only Ca until the corals in your tank consume the excess alk. Then start dosing ca and alk.

 

[lrhorer]

Two part additives, only dosing the calcium part, will accomplish increasing calcium without impacting ph or alkalinity levels.

Well, it wouldn't hurt to increase calcium by itself a bit, but that wouldn't lower the alkalinity.

If calcium and alk are good (and STABLE)

Well, as I said, my alkalinity is high. The water around here makes concrete look like foam rubber.

I'd recommend direct feeding of lps

I am already doing so, although I am not certain how good the foods I am using are. I am using Marine Snow and Phytoplex. I am goingto try some Reef Roids to see how they do.

and if that still doesn't work over time, you can always buy an ICP test like Triton, and see what it says.

If I don't see some obvious growth in the next few months, I will give it a try.

Chemistry levels are #1, stability of those levels is #2

As stated, the levels are a bit off, but not horrible, I don't think. Stability is good.

food is #3

Yeah, I don't see a lot of obvious food consumption like I have seen in videos of other people's tanks.

and finally trace elements might be #4.

I am dosing Iodine, Magnesium, and Strontium per recommendations. Magnesium levels are stable around 1300ppm.

This assumes you have appropriate lighting

I think so. I have moved the frags around to where they seem happiest, and none are in either the brightest nor the darkest areas except for a couple of mushrooms that seem to like it best in the darkest part of the tank. All of them respond as expected to the light cycles.

and don't have a disease or organism predating on your lps corals.

Well I did have something eating my Button Polyps: they were disappearing one or two at a time. Other than that, the corals aren't diminishing, just not growing like I believe they should. The colors seem pretty good.

 

[lrhorer]

What is the alk of the water you are using for water changes?

13

What is your mag?

1300

Are you dosing?

Magnesium, Strontium, and Iodine, yes.

If I were you, I would make sure the alk of my water change water was below 12

That's easier said than done. I am buying the water from my LFS. I suppose I could mix my own using water from my water softener.

mag was acceptable, and then dose only Ca until the corals in your tank consume the excess alk. Then start dosing ca and alk.

So far they haven't.

 

[bertoni]

13 dKH probably is safe enough. If stopping the alkalinity dosing doesn't help, then I'd personally just ignore the dKH. Some tanks, especially those getting carbon dosing, seem to have problems with a higher dKH level, but not always. Other than that, 13 dKH seems to be acceptable for our systems.

 

[lrhorer]

OK. Nothing seems actually stressed, so I'm not worried, just not thrilled, either.

 

[dkeller_nc]

You mentioned that your tap water was very hard. But presuming that you're using an RODI system to produce your top-off water, that shouldn't actually matter. If you're not and you're just using something like Amquel or Prime to remove chlorine/chloramine, or you're on a well, you might consider going to a RODI system, since chlorine/chloramine isn't the only issue with untreated tap water.

 

[Uncle99]

When you get water from LFS, your asking for trouble
Make your own and ensure 0 tds is maintained.
Otherwise “sally” whose in grade 11 may be your water master

 

[clevername]

i hope someone steps in with the details but after a certain level of ALK the soft part (internal) corals will outgrow the calcium structure. Literally the calcium skeleton cant grow fast enough.

I reference it like this, adding a NOS tank in a hybrid. YES you can get really fast results but internally the engine is going to be stressed long term and wear down. (not the best analogy). In this case 100% raising ALK will make corals grow faster (fact) BUT at some point the other parts of the coral which DONT use ALK cant keep up.

 

[bertoni]

If the alkalinity starts dropping much below 6 dKH or so, very roughly, the coral might not be able to grow because it will have trouble producing a skeleton. That 6 dKH number is rather pessimistic, but there are a lot of variables involved in a more precise answer.

 

[bustybones]

my tank has gone through same process, I daily dosed aqua vitro 8.4 to raise carbonate alkalinity. do this slowly. I tested 3x a day to gain data points to find the rate of consumption. Am, mid afternoon, and evening. Friday my alkalinity was 6.0, my calcium was over 500 and magnesium was 1600. Today my alkalinity is 8.2

Sent from my SM-G955U using Tapatalk

 

[lrhorer]

You mentioned that your tap water was very hard. But presuming that you're using an RODI system to produce your top-off water, that shouldn't actually matter.

No, there are two main LFS here in San Antonio. One has a a DI system, the other a RO system. The DI is more expensive and less accessible. (They close early.)

 

[lrhorer]

When you get water from LFS, your asking for trouble
Make your own and ensure 0 tds is maintained.
Otherwise "œsally" whose in grade 11 may be your water master

No, I know everyone at both stores, and have for years. Decades, actually. I started this hobby when I was 13. I will be 60 later this year.