dKh in sps tank: wich is the best value?

gaetanocallista · 04/19/2009, 10:42 AM

This is one of the most controversial value: one of the most italian sellers said me that he tested tropical water and see that dKh is 6. Usually I read that it's important maintain the range about 7 - 9.
Now I want know (for sps tank) if it's better to have a value of 6 - 7 ore more.
I see that a lot of people have 9 or more (10 -12) and others have lower values!
Wat do you think about that?

Helter Skilter · 04/19/2009, 12:12 PM

I prefer to run around 9-10dkh. I have had Acropora tissue slough around 7dkh, but haven't seen any negative affects from an ALk level as high as 14dkh. I guess I try to error on the side of caution, without going overboard.

reefnetworth · 04/19/2009, 12:17 PM

i keep mine @ 10.5 dKH.
Mg @ 3X's the Ca level of 470-475, Mg @ 1400 - 1475.

tatuvaaj · 04/19/2009, 12:23 PM

Quote:

Originally posted by Helter Skilter
I prefer to run around 9-10dkh.

Me too

Raising it closer to 4 meq/l while maintaining calcium around 420 ppm increases precipitate inside pumps too much for me (pH around 8.3). Too much work

gaetanocallista · 04/20/2009, 01:28 AM

Anyone lower (6 - 7) dKh?

HighlandReefer · 04/20/2009, 05:25 AM

Randy recommends maintaining an alk. level between 7-11 dKH. He has stated that it does not matter to him as long as it remains between those levels.

Some of your sps, vodka dosers and ULN hobbyists claim that they will get tip burn in many of their coral if the alk. rises above I believe around 8 dKH. They keep it at 7-8 dKH. I have not experienced this.

I keep my alk. at around 11 dKH and find this helps to keep my pH above 7.8 due to high CO2 levels in my home. I have had no problems with this.

I have elevated my alk. level up to 16 dKH and saw no problems at this level. There is some research that indicated high levels of alk. promote more calcification in coral where calcification increased proportionately as the levels increased up to around 21 dkH. You will get a lot of precipitation at these levels on your glass....etc. It will take a lot of alk. supplement to maintain these levels also.

gaetanocallista · 04/20/2009, 05:48 AM

Quote:

Originally posted by HighlandReefer
Randy recommends maintaining an alk. level between 7-11 dKH. He has stated that it does not matter to him as long as it remains between those levels.

Some of your sps, vodka dosers and ULN hobbyists claim that they will get tip burn in many of their coral if the alk. rises above I believe around 8 dKH. They keep it at 7-8 dKH. I have not experienced this.

That is the question!
Burn tips at dkh 9

Unfortunately it's also my experience!

HighlandReefer · 04/20/2009, 06:02 AM

This subject would be better discussed with Genetics, as he is one of the very knowledgeable hobbyist's who has experienced this.

IMHO, it seems to be found in the ULN environment more frequently, where nitrate and phosphate are being kept to minimal levels. Perhaps the phosphate and/or nitrate become too low and this is the cause?

tatuvaaj · 04/20/2009, 09:47 AM

I'm pretty sure that this problem is not caused by low inorganic nutrient concentrations alone. Organic carbon dosing and "ULNS" isn't anything new after all. It's been around for at least 10 years and many very successful hobbyists have had "ULNS" long before it was called that

Maybe it is caused by some other components commercial ULN systems include? Or maybe it is the lack of food available to fast growing corals?

BigJay · 04/20/2009, 10:58 AM

Alk is between 10-12, with no burnt tips to speak of.

It's hard to stay much lower than that with a calcium reactor and frequent water changes with reef crystals salt at 12 DKH out of the bucket.

fourzero · 04/20/2009, 04:46 PM

You may be on to something here. Zooxanthellae concentration is reduced in ULNS. They may act as a "shield" of sorts for certain wavelengths of light.

I have not witnessed burnt tips, and I have undetectable levels of NO3/PO4 and high alk (4 meq/L, or 11.2dkh). Just thinking aloud. I too would like Genetics or Randy's input here.

Quote:

Originally posted by HighlandReefer
This subject would be better discussed with Genetics, as he is one of the very knowledgeable hobbyist's who has experienced this.

IMHO, it seems to be found in the ULN environment more frequently, where nitrate and phosphate are being kept to minimal levels. Perhaps the phosphate and/or nitrate become too low and this is the cause?

Reefer08 · 04/20/2009, 09:24 PM

Alkalinity of 6.5-7.5 is the best for SPS

tmz · 04/21/2009, 12:05 AM

I don't think there is a best level for all systems.

As noted above the optimal level may depend on many variables, including: nutrient availability, excess or paucity, food, the levels of alkalinity to which corals have adapted , the amount consumed by calcareous organisms in the tank and the bacterial activity in the tank; to name a few.

Many of the advocates of ultra low nutrient systems such as zeovit systems recommend lower alkalinity in these systems. Perhaps as Tatu suggests corals and/or their zooxanthelae in ultra low nutirent systems don't get enough nourishment to sustain more rapid growth levels encouraged by higher alakalinity, In any case it is pretty clear that higher alkalinity makes it easier for corals to calcify .

The norm for natural seawater is generally around 7 dkh but in a closed system levels can deplete rather quickly if growth is occurring so a margin over that amount is often chosen.If it falls much lower it can discourage calcification.

FWIW I keep mine on the high side at 11.5 to 12dkh with high calcium 540ppm and ph around 8,25, phosphate at .07ppm and nitrate at 2 to 5ppm I'm happy with the results for sps and other corals. I do not experience much abiotic precipitation but do see good sps growth.

Helter Skilter · 04/21/2009, 07:55 PM

Someone please correct me if I'm wrong, but I believe having your Alk higher than natural SW offsets some of the problems associated with the lower than optimal pH that reef tanks can experience. The higher Alk helps minimize the pH swings, and also helps make up for reduced calcification rates of SPS in water with a lower than natural pH.

HighlandReefer · 04/21/2009, 08:18 PM

I keep my alk. at around 11.5 for this reason also. If I let it drop below 11.0 my pH will drop below where I like it (7.9 or above). Of course I am running kalk. If I let my alk. get much higher, then I will start to get a calcium carbonate haze just above the sand level on my glass.

elijaher · 04/21/2009, 08:32 PM

The most important about alk need not to swing.

tmz · 04/21/2009, 09:10 PM

I don't think higher alkalinity will offset day night ph swings or at least I don't understand why it would. I agree it will,in my opinion , make calcification easier and offset some of the difficulty corals can experience with this function at lower ph levels by making bi carbonate more readily available.

HighlandReefer · 04/22/2009, 03:39 AM

The higher the alk. the higher the buffering compacity and hence the lower the pH swings at night due to increased CO2.

The Relationship Between Alkalinity and pH.
http://www.advancedaquarist.com/issues/may2002/chem.htm

From Randy's article:

"The most important fact to reefkeepers is that the buffering due to bicarbonate and carbonate, at a given pH, is directly related to the carbonate alkalinity. If you double the alkalinity, you double b, and hence have twice as much buffering due to the carbonate and bicarbonate system. In normal seawater, the carbonate/bicarbonate system provides a substantial portion of the total buffering (which is quantified below). Consequently, marine aquaria with higher alkalinity tend to have greater buffering against pH swings."

tmz · 04/22/2009, 08:18 AM

Thanks Cliff, I've read that before and knew that once. Just couldn't find it in my head last night.

HighlandReefer · 04/22/2009, 08:33 AM

I have those senior moments myself.

tmz · 04/22/2009, 09:02 AM

Quote:

Originally posted by HighlandReefer
I have those senior moments myself.

Exactly.If it wasn't so silly;I'd worry.

moonyguy · 04/22/2009, 09:21 AM

Mine is at Alk 6.1 and Ca is 410. Slowly raising it to 6.5.

tatuvaaj · 04/22/2009, 01:28 PM

The problem is that you'll need very high alkalinity if you try to compensate for elevated pCO2 commonly found in indoor air and CO2 produced in aquarium. I think it more useful to worry about CO2 than alkalinity when battling chronically low pH.

Just my $0.02

HighlandReefer · 04/22/2009, 01:33 PM

Tatu,

Not that I disagree with you, but what is the difference between pCO2 & CO2 for us non-chemist types.

tatuvaaj · 04/22/2009, 01:47 PM

HighlandReefer,

Hey I'm not chemist either !

pCO2 means partial pressure and it is used to describe amount of gas in a sample of mixed gases like air. I'm sure no one will care even if we leave the 'p' out

[Edit: you'll find pCO2 used in many scientific texts, like here: http://www.sciencemag.org/cgi/conten.../5447/2043a/F1 ]

04/19/2009, 10:42 AM	#1
gaetanocallista Registered Member Join Date: Aug 2004 Location: Italy Posts: 141	dKh in sps tank: wich is the best value? This is one of the most controversial value: one of the most italian sellers said me that he tested tropical water and see that dKh is 6. Usually I read that it's important maintain the range about 7 - 9. Now I want know (for sps tank) if it's better to have a value of 6 - 7 ore more. I see that a lot of people have 9 or more (10 -12) and others have lower values! Wat do you think about that?

04/19/2009, 12:12 PM	#2
Helter Skilter OT Community Organizer Join Date: Feb 2007 Location: Lake in the Hills, IL Posts: 2,357	I prefer to run around 9-10dkh. I have had Acropora tissue slough around 7dkh, but haven't seen any negative affects from an ALk level as high as 14dkh. I guess I try to error on the side of caution, without going overboard. __________________ “I don't get nearly enough credit in life for the things I manage not to say.” ― Meg Rosoff Current Tank Info: 20 gallon cube with some coral and stuff

04/19/2009, 12:17 PM	#3
reefnetworth Premium Member Join Date: Mar 2006 Location: U.S.A. Posts: 3,810	i keep mine @ 10.5 dKH. Mg @ 3X's the Ca level of 470-475, Mg @ 1400 - 1475. __________________ GIVE A MAN A FISH, YOU FEED HIM FOR A DAY. TEACH A MAN TO FISH, HE FEEDS HIMSELF FOR LIFE. (NEVER, underestimate another man's greed) Current Tank Info: SPS dominated barebottom display with BB sump since 2005, most consistant parameters in 19+ years of reefkeeping.

04/20/2009, 05:25 AM	#6
HighlandReefer Team RC Member Join Date: Aug 2008 Location: Highland, Maryland Entomologist Posts: 14,591	Randy recommends maintaining an alk. level between 7-11 dKH. He has stated that it does not matter to him as long as it remains between those levels. Some of your sps, vodka dosers and ULN hobbyists claim that they will get tip burn in many of their coral if the alk. rises above I believe around 8 dKH. They keep it at 7-8 dKH. I have not experienced this. I keep my alk. at around 11 dKH and find this helps to keep my pH above 7.8 due to high CO2 levels in my home. I have had no problems with this. I have elevated my alk. level up to 16 dKH and saw no problems at this level. There is some research that indicated high levels of alk. promote more calcification in coral where calcification increased proportionately as the levels increased up to around 21 dkH. You will get a lot of precipitation at these levels on your glass....etc. It will take a lot of alk. supplement to maintain these levels also. __________________ Cliff Babcock Intestests: Digital Microscopy; Marine Pest Control; Marine Plants & Macroalgae Current Tank Info: 180 g. mixed reef system

04/20/2009, 06:02 AM	#8
HighlandReefer Team RC Member Join Date: Aug 2008 Location: Highland, Maryland Entomologist Posts: 14,591	This subject would be better discussed with Genetics, as he is one of the very knowledgeable hobbyist's who has experienced this. IMHO, it seems to be found in the ULN environment more frequently, where nitrate and phosphate are being kept to minimal levels. Perhaps the phosphate and/or nitrate become too low and this is the cause? __________________ Cliff Babcock Intestests: Digital Microscopy; Marine Pest Control; Marine Plants & Macroalgae Current Tank Info: 180 g. mixed reef system

04/20/2009, 01:28 AM	#5
gaetanocallista Registered Member Join Date: Aug 2004 Location: Italy Posts: 141	Anyone lower (6 - 7) dKh?

04/20/2009, 09:47 AM	#9
tatuvaaj Pro-Protozoa Join Date: Nov 2000 Location: Tampere, Finland Posts: 1,228	I'm pretty sure that this problem is not caused by low inorganic nutrient concentrations alone. Organic carbon dosing and "ULNS" isn't anything new after all. It's been around for at least 10 years and many very successful hobbyists have had "ULNS" long before it was called that Maybe it is caused by some other components commercial ULN systems include? Or maybe it is the lack of food available to fast growing corals? __________________ Tatu Vaajalahti Tampere, Finland Current Tank Info: 240 gal + 50 gal sump,SDSB,LR,ATB Medium, 2x250W HQI + actinic,Balling

04/20/2009, 10:58 AM	#10
BigJay Registered Member Join Date: Mar 2008 Location: Southlake, Texas Posts: 1,872	Alk is between 10-12, with no burnt tips to speak of. It's hard to stay much lower than that with a calcium reactor and frequent water changes with reef crystals salt at 12 DKH out of the bucket. __________________ PBITAWA

04/20/2009, 09:24 PM	#12
Reefer08 Moved On Join Date: Apr 2008 Location: SoCal Posts: 2,812	Alkalinity of 6.5-7.5 is the best for SPS

04/21/2009, 12:05 AM	#13
tmz ReefKeeping Mag staff Join Date: Apr 2006 Location: West Seneca NY Posts: 27,691	I don't think there is a best level for all systems. As noted above the optimal level may depend on many variables, including: nutrient availability, excess or paucity, food, the levels of alkalinity to which corals have adapted , the amount consumed by calcareous organisms in the tank and the bacterial activity in the tank; to name a few. Many of the advocates of ultra low nutrient systems such as zeovit systems recommend lower alkalinity in these systems. Perhaps as Tatu suggests corals and/or their zooxanthelae in ultra low nutirent systems don't get enough nourishment to sustain more rapid growth levels encouraged by higher alakalinity, In any case it is pretty clear that higher alkalinity makes it easier for corals to calcify . The norm for natural seawater is generally around 7 dkh but in a closed system levels can deplete rather quickly if growth is occurring so a margin over that amount is often chosen.If it falls much lower it can discourage calcification. FWIW I keep mine on the high side at 11.5 to 12dkh with high calcium 540ppm and ph around 8,25, phosphate at .07ppm and nitrate at 2 to 5ppm I'm happy with the results for sps and other corals. I do not experience much abiotic precipitation but do see good sps growth. __________________ Tom Current Tank Info: Tank of the Month , November 2011 : 600gal integrated system: 3 display tanks (120 g, 90g, 89g),several frag/grow out tanks, macroalgae refugia, cryptic zones. 40+ fish, seahorses, sps,lps,leathers, zoanthidae and non photosynthetic corals.

04/21/2009, 07:55 PM	#14
Helter Skilter OT Community Organizer Join Date: Feb 2007 Location: Lake in the Hills, IL Posts: 2,357	Someone please correct me if I'm wrong, but I believe having your Alk higher than natural SW offsets some of the problems associated with the lower than optimal pH that reef tanks can experience. The higher Alk helps minimize the pH swings, and also helps make up for reduced calcification rates of SPS in water with a lower than natural pH. __________________ “I don't get nearly enough credit in life for the things I manage not to say.” ― Meg Rosoff Current Tank Info: 20 gallon cube with some coral and stuff

04/21/2009, 08:18 PM	#15
HighlandReefer Team RC Member Join Date: Aug 2008 Location: Highland, Maryland Entomologist Posts: 14,591	I keep my alk. at around 11.5 for this reason also. If I let it drop below 11.0 my pH will drop below where I like it (7.9 or above). Of course I am running kalk. If I let my alk. get much higher, then I will start to get a calcium carbonate haze just above the sand level on my glass. __________________ Cliff Babcock Intestests: Digital Microscopy; Marine Pest Control; Marine Plants & Macroalgae Current Tank Info: 180 g. mixed reef system

04/21/2009, 08:32 PM	#16
elijaher Registered Member Join Date: Sep 2007 Location: Kansas City,Missouri Posts: 1,188	The most important about alk need not to swing.

04/21/2009, 09:10 PM	#17
tmz ReefKeeping Mag staff Join Date: Apr 2006 Location: West Seneca NY Posts: 27,691	I don't think higher alkalinity will offset day night ph swings or at least I don't understand why it would. I agree it will,in my opinion , make calcification easier and offset some of the difficulty corals can experience with this function at lower ph levels by making bi carbonate more readily available. __________________ Tom Current Tank Info: Tank of the Month , November 2011 : 600gal integrated system: 3 display tanks (120 g, 90g, 89g),several frag/grow out tanks, macroalgae refugia, cryptic zones. 40+ fish, seahorses, sps,lps,leathers, zoanthidae and non photosynthetic corals.

04/22/2009, 03:39 AM	#18
HighlandReefer Team RC Member Join Date: Aug 2008 Location: Highland, Maryland Entomologist Posts: 14,591	The higher the alk. the higher the buffering compacity and hence the lower the pH swings at night due to increased CO2. The Relationship Between Alkalinity and pH. http://www.advancedaquarist.com/issues/may2002/chem.htm From Randy's article: "The most important fact to reefkeepers is that the buffering due to bicarbonate and carbonate, at a given pH, is directly related to the carbonate alkalinity. If you double the alkalinity, you double b, and hence have twice as much buffering due to the carbonate and bicarbonate system. In normal seawater, the carbonate/bicarbonate system provides a substantial portion of the total buffering (which is quantified below). Consequently, marine aquaria with higher alkalinity tend to have greater buffering against pH swings." __________________ Cliff Babcock Intestests: Digital Microscopy; Marine Pest Control; Marine Plants & Macroalgae Current Tank Info: 180 g. mixed reef system Last edited by HighlandReefer; 04/22/2009 at 03:46 AM.

04/22/2009, 08:18 AM	#19
tmz ReefKeeping Mag staff Join Date: Apr 2006 Location: West Seneca NY Posts: 27,691	Thanks Cliff, I've read that before and knew that once. Just couldn't find it in my head last night. __________________ Tom Current Tank Info: Tank of the Month , November 2011 : 600gal integrated system: 3 display tanks (120 g, 90g, 89g),several frag/grow out tanks, macroalgae refugia, cryptic zones. 40+ fish, seahorses, sps,lps,leathers, zoanthidae and non photosynthetic corals.

04/22/2009, 08:33 AM	#20
HighlandReefer Team RC Member Join Date: Aug 2008 Location: Highland, Maryland Entomologist Posts: 14,591	I have those senior moments myself. __________________ Cliff Babcock Intestests: Digital Microscopy; Marine Pest Control; Marine Plants & Macroalgae Current Tank Info: 180 g. mixed reef system

04/22/2009, 09:21 AM	#22
moonyguy Premium Member Join Date: May 2005 Location: Tucson, Arizona Posts: 577	Mine is at Alk 6.1 and Ca is 410. Slowly raising it to 6.5.

04/22/2009, 01:28 PM	#23
tatuvaaj Pro-Protozoa Join Date: Nov 2000 Location: Tampere, Finland Posts: 1,228	The problem is that you'll need very high alkalinity if you try to compensate for elevated pCO2 commonly found in indoor air and CO2 produced in aquarium. I think it more useful to worry about CO2 than alkalinity when battling chronically low pH. Just my $0.02 __________________ Tatu Vaajalahti Tampere, Finland Current Tank Info: 240 gal + 50 gal sump,SDSB,LR,ATB Medium, 2x250W HQI + actinic,Balling

04/22/2009, 01:33 PM	#24
HighlandReefer Team RC Member Join Date: Aug 2008 Location: Highland, Maryland Entomologist Posts: 14,591	Tatu, Not that I disagree with you, but what is the difference between pCO2 & CO2 for us non-chemist types. __________________ Cliff Babcock Intestests: Digital Microscopy; Marine Pest Control; Marine Plants & Macroalgae Current Tank Info: 180 g. mixed reef system

04/22/2009, 01:47 PM	#25
tatuvaaj Pro-Protozoa Join Date: Nov 2000 Location: Tampere, Finland Posts: 1,228	HighlandReefer, Hey I'm not chemist either ! pCO2 means partial pressure and it is used to describe amount of gas in a sample of mixed gases like air. I'm sure no one will care even if we leave the 'p' out [Edit: you'll find pCO2 used in many scientific texts, like here: http://www.sciencemag.org/cgi/conten.../5447/2043a/F1 ] __________________ Tatu Vaajalahti Tampere, Finland Current Tank Info: 240 gal + 50 gal sump,SDSB,LR,ATB Medium, 2x250W HQI + actinic,Balling