[jimw369]

My 90 gallon tank has been running for 5-6 mos now. I suppose I have done what many do and have put several corals including a clam and now my calcium seems stuck at 350-360ppm. I am dosing the recommended amount and the Ca level stays the same.
I need my Ca to be between 400-450 ideally so what do I do to raise it?

Does magneseum play a role in this somehow?

My PH holds pretty steady around 7.8-8.3 depending on the time of day I do my testing. Why does this change from morning to evening. I have read Ph needs to be stable. Is my Ph within tolerable limits? If not, what can I do to make the Ph more stable.

My DHK or KH runs pretty steady at 7-8. This is the low end of the scale and would like to see it between 9-11. What can I do to raise these numbers.

[glampka]

I'm sure you'll find this helpful: A Simplified Guide to the Relationship Between Calcium, Alkalinity, Magnesium and pH by Randy Holmes-Farley - Reefkeeping.com

[pogodzib]

You should raise both your calcium and alkalinity using either a two part solution (commercial or diy) and/or kalk water. On a 90 gal tank, the commercial additive costs can add up, so you may want to look into the Randy Holmes-Farley two part solution. Here's a link.

An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com

If your alk is raised, more than likely the pH swing won't be as much. In the past, my tank would run with a pH of between 7.7-7.8 all winter long, every winter and it never caused any problems. When your tank lights come on the pH will start rising and will generally continue to rise until the lights go off. At htat time the pH will start dropping until the lights come on again. Using a refugium with light cycle that is reversed from the lights on your display tank will also help to minimize the swings.

Magnessium can play a minor role in the levels that are attainable for calcium and alkalinity, but it should be very minor on a 5-6 month old tank. If you test for magnessium and know where your levels are at then you would know if you need to do something.

[jimw369]

Thank you Glampka.

I have quickly glanced at the articles you have suggested for reading. They go into great detail regarding the relationship between Calcium, PH and alkalinity but they just say raise this and lower that. They talk about using Baking Soda, vinegar and some pickling juice I can buy at the supermarket. Is there an article that tells me how to dose these things into my tank and in what amounts to raise particular things to a certain level?

Is all this information necessary to learn to have a successful reef tank or can my LFS provide me with an "all in one" product that takes care of these things automatically?

[jimw369]

Thanks both of you for the great resources.

Pogodzib recomended reading that talks about using Dow Flake. Is this why I see group buys of this stuff on other saltwater forums? And...isnt Dow flake the same as Rock salt?

In your opinions, are the home made additives necessary to use over the store bought additives If I want to carry a large bio-load in my tank and more effective? I would assume most of us someday want to have our tanks full of corals and fish!

[pogodzib]

Your LFS can provide you with a two part additive that will raise you calcium and alkalinity and they should also be able to provide you with a magnesium supplement. The costs can get substantial if you end up having a lot of SPS corals or clams, which is where a DIY solution has a big advantage.

Here's a link to a calculator that you can use to figure out dosing amounts. You'll be able to see many different options that you can use to raise your alk, calcium, and magnessium.

Reef Chemistry Calculator

Yes, that is why you see the Dow Flake group buys. Dow flake is Calcium Chloride. There are plenty of other manufacturers that make calcium chloride, but nobody has tested most of them to ensure that they don't contain contaminants. http://www.buckeyefieldsupply.com/sh...owspecials=124 sells Dowflake and MagFlake in smaller quantities.