Chemistry and Color

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djkms

Reef Shark
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#1
#1
I recently had a member ask me;
My dkh is between 8.5-9.5. 8.5 was when stuff browned and 9.5 is when the corals are doing perfect. How is yours so low and corals doing ok?
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I keep my alkalinity from 7-7.5 in my 225. For those who have seen my system is it mostly SPS with a few LPS here and there (no softies). On my previous 125 I used to keep my alkalinity between 8.5-9.5.

So why the difference between the systems? Nutrients. In my 125 my NO3 was usually around 5ppm and PO4 around .04-.08. In my 225 I keep my NO3 around .1-.2 and PO4 around 0-.02. I would say my 125 was a high nutrient system and my 225 is a semi-ulns (ultra low nutrient system)

It has been my experience that keeping alk low for ulns and alk high for high nutrient systems provides the best solution for color and growth for stony corals. Of course everyone's mileage may very and I am sure there are fantastic systems that are the opposite of what I say, these have been my findings though.

My experience was the same as the above quote. Anytime I dropped below 8 in my 125 I struggled with browning corals. Conversely in my 225 anytime I go over 8 I get burnt tips on my acros.

As a matter of fact while cruising RC I found a fantastic thread which basically confirms this information:
http://www.reefcentral.com/forums/showthread.php?t=2253547

The thread actually delves into the subject a little further to include light intensity into the equation. I can't really comment on that aspect because my 125 was lit by LED and my 225 is halide/t5 combo.

I hope this information can help some of you. Any questions let me know!
 
SynDen

SynDen

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#2
#2
Good info! Clarifies a lot and confirms some suspicions. I just replaced my t5s with new let t5s and have a lot more light. Been also running gfo and carbon, so my nutrients are very low but my alk has been over 9 for awhile now. Most of my corals looks great, mostly the softies and lps but my red planet acro has browned out somewhat recently. I will have to bring my alk down and see if that helps. Thanks for the info
 
SynDen

SynDen

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#3
#3
Curious what salt do use?
 
SynDen

SynDen

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#5
#5
Finally finished reading that thread on RC and I have to say it was one of the most informative reads. Clarified a lot of questions, thanks for sharing. I'd defiantly recommend that everyone read it
 
SynDen

SynDen

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#6
#6
Well since I am using kent salt, which has very high alk, 10-11dkh range, I have been thinking about how to increase nutrients to increase colors while still keeping algae under control, since letting the alk drop to the 7.5 range may not be possible with that salt.
So over the weekend I switch my GFO/Carbon reactor to run only when all my lights are on, about 4.5 hours a day currently, instead of 24/7 like it was. I also increased feeding a bit. Think I may add another tang to the tank as well to help ensure algae stays down, but may also try using some acropower on the tank too. Thoughts?
 
SynDen

SynDen

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#8
#8
How you keep it low when mixing it straight out of the bag at 1.025 sal it sits at a bit over 10 dkh? Although I do a 10% wc once a week, so your system consumes that much alk in those two weeks between wc?
although I will say with my alk at about 10 most everything in the tank looks great except my red planet which is very light brown, and for that reason I need to either lower my alk or increase my nutrient levels to hopefully get it back to that nice deep red with light green
 
SynDen

SynDen

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#11
#11
Man you must have quite a bit in there eating up the alk then. My tank still fairly young and it doesn't go through very much alk. I don't dose at all and mine usually around 9.8
 
SynDen

SynDen

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#13
#13
yep that would do it. I have a few sticks too but they mostly all very small frags at this point. but really want them to grow out nice colorful and healthy colonies. Have a fair amount of LPS and Softies too but they are pretty undemanding
 
SkyDiv3r17

SkyDiv3r17

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#14
#14
I use Kent as well and can't keep my dkh above 8 haha. I've only had one acro Brown on me. I believe my nutrients are low because of my kulerpa and skimmer. I'm trying to bring my alk up but even with dosingv it ain't really working for some reason.
 
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goslugsgo

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#15
#15
SkyDiv3r17;308783 said:
I use Kent as well and can't keep my dkh above 8 haha. I've only had one acro Brown on me. I believe my nutrients are low because of my kulerpa and skimmer. I'm trying to bring my alk up but even with dosingv it ain't really working for some reason.
Click to expand...
How old is your test kit?
 
D

djkms

Reef Shark
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#16
#16
SkyDiv3r17;308783 said:
I use Kent as well and can't keep my dkh above 8 haha. I've only had one acro Brown on me. I believe my nutrients are low because of my kulerpa and skimmer. I'm trying to bring my alk up but even with dosingv it ain't really working for some reason.
Click to expand...
How are you dosing your buffer and calcium?
What product are you using?
How often are you dosing?
What is your systems consumption rate (CA, dKH)?
Where are you dosing it (sump, main tank, etc)
How are you maintaining Magnesium?
What is your Calcium and Magnesium level?

If you are Ionic imbalanced you could be precipitating it out, especially if your magnesium is low. From previous experience (haven't used Kent Salt for a couple years) Kent is very high in CA and low in Magnesium.
 
SynDen

SynDen

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#17
#17
Hmm, well I think Kent's mag is much higher nowadays, but so is the alk and calc. For me my alk stays right around 9.5 or so, calc at500 and my mag lately is 1500+. I don't dose anything either I just do like a 15% water change once a week. So you got to have something eating up you alk really fast or like kris mentioned you have an imbalance somewhere that is precipitating it out
 
SkyDiv3r17

SkyDiv3r17

Butterfly Fish
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#18
#18
goslugsgo;308799 said:
How old is your test kit?
Click to expand...
One month. lol
djkms;308805 said:
How are you dosing your buffer and calcium? Calcium has always seemed to be good. I want to say like 450? Havent check that in a little while because of my alk being low.
What product are you using? Alk powder that I put in 1/2 gallon of rodi water and let it dissolve.
How often are you dosing? Roughly once a day for three days/week. Just trying to up my alk by adding about a 1/3 of that 1/2 gallon /day.
What is your systems consumption rate (CA, dKH)? I'm not that far into it yet.. I have a 9+inch birdnest, a 5+in birdnest, and a 15+ inch Hollywood stunner, and some other smaller sps.
Where are you dosing it (sump, main tank, etc)? In the main tank by my powerhead.
How are you maintaining Magnesium? I don't, just with water changes.
What is your Calcium and Magnesium level? Calc around 450 I believe. I don't test mag right now.

If you are Ionic imbalanced you could be precipitating it out, especially if your magnesium is low. From previous experience (haven't used Kent Salt for a couple years) Kent is very high in CA and low in Magnesium.
Click to expand...
Sooo I'm guessing I should get a mag test kit?
 
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