DkH

[fencer]

What is the best DkH to have optimal growth for SPS. Assuming all other parameters are adjusted or okay. Please choose one and round up or down to the nearest whole number

[mark]

not sure but might do a survey of TOTM write-ups.

[marie]

I don't know that there is a "best" DKH, anything within the parameters you set for the poll is fine and the dkh in my tank bounces around all those numbers

[globaldesigns]

Mine is at 7, but that is because I run Zeovit, otherwise IMO 9-11 is good

[fishytime]

Dont take my TOTM writeup as something to go by....my dkh is low and Ive been struggling to get it up.....wait a second....that didnt sound good

[whatcaneyedo]

For me I have to keep my alkalinity up around 11-12 dkh in order to keep my pH up in the 8.0- 8.2 range. There is so much carbon dioxide in my house (especially in the winter) that if I let my alkalinity fall down to 7-8 my pH will also drop to 7.6-7.8

I do everything from drawing my skimmers air from outside to dosing kalkwasser in conjunction with my Calcium reactor to growing macro algae and leaving the top of my system open for better gas exchange. But still I fight with low pH.

[untamed]

Originally Posted by whatcaneyedo

For me I have to keep my alkalinity up around 11-12 dkh in order to keep my pH up in the 8.0- 8.2 range. There is so much carbon dioxide in my house (especially in the winter) that if I let my alkalinity fall down to 7-8 my pH will also drop to 7.6-7.8

I do everything from drawing my skimmers air from outside to dosing kalkwasser in conjunction with my Calcium reactor to growing macro algae and leaving the top of my system open for better gas exchange. But still I fight with low pH.

Man...I could have written the exact same thing...word for word. My alk is higher than I would like (10) for exactly this reason. I've learned some very interesting stuff about my Kalk reactor as I've tried to use it to prevent overnight pH lows. (when you are hitting nightly lows of pH 7.6...you just can't ignore pH at that point)

[sphelps]

The way I see it is if you're pH is low at a natural alk level you've got other problems to address that aren't really solved by simply adding more carbonate to increase alkalinity. More than likely the amount of CO2 in the water is too high and instead of covering this issue with something else you should be looking at the source of the problem. 99% of the time it comes down to the calcium reactor for obvious reason, it runs on CO2. The problem is very few understand the science behind these reactors and simply set an internal or effluent pH and figure that's good. However there is much more to consider including media type, reactor design, effluent flow rate, circulation flow rate, and CO2 flow rate.

For example, you find your tank pH is lower than normal say 7.8. First off you know that tanks using a Ca reactor will usually have a little lower pH than tanks using other methods, but I don't think lower than 8.0 mid-day is normal. So what's the problem? Too much CO2? Most likely but what's the solution? Most would simply bump the alkalinity up by increasing the output of the reactor by increasing the CO2 input which will actually add even more CO2 to the tank. What you should do is adjust your reactor, you've obviously got too much dissolved CO2 coming out of the reactor, meaning either too much CO2 is being added, flow rates are too high or a combination of both. The reactor may also be too small for the demand of the system or be of poor quality and design.

Another alternative to adding more CO2 would be to add kalkwasser instead which actually reacts with the CO2 in the tank promoting a higher and stable pH.

I don't think anything over 10 dkh is good for SPS, mainly because I've never seen a successful SPS tank with an alkalinity that high. Even if you go through RC TOTM I don't think you'll see anything with much higher than 9 dkh.

[RuGlu6]

There is NO best dkh, per say.
it will depend on your calcium
higher calcium requires higher alkalinity and visa versa.

[fencer]

I assuming a Ca of 450 ppm/ Mg 1400 ppm is good for SPS. My DkH hovers around 8( a bit lower) which is required for Ultralith program. I run a Calcium reactor and have a lot of rock in the tank. I am always interested in how a person who gets a tiny frag can grow into a monster within a year. "Marie's" tank comes to mind. I do realize some corals grow faster than others. I was thinking high DkH and Ca may aid in Ca uptake by Acros. What are they doing riight that I am not. I guess I really need to see someones tank (locally) who has been raising(growing) SPS successfully.