trouble raising calcium

[Dr.Nate]

Well, I have a FOWLR setup, but am getting ready for corals! My lights should be here this week as well as my powerheads. So I got a Calcium test kit, and I've been adding Kent's liquid calcium every other day for about a month now. My calcium is only at 360 ppm. My dkh is at 12. Is there a better way to slowly raise the calcium to 400-450?

 

[steve-s]

Is there a better way to slowly raise the calcium to 400-450?

Water changes depending on your saltmix. If IO salts, it's most likely the cause so it won't help.

How much Ca are you adding and to what water volume?

Cheers
Steve

 

[Dr.Nate]

yep, I use instant ocean. I was adding 1 tsp. of kent's liquid calcium every other day for about a month to my 55 gal. But now that I know Ca is low, I've been adding 2 tsp every day....still doesn't seem to help.

 

[steve-s]

You would need to use about 3-4 teaspoons a day (20 ml) to achieve and increase to 400ish ppm. You're most likely only adding enough to maintain the level, not actually increase it. You'll need about 100 ml just to correct this imbalance. Might be an idea to pick up some dry Turbo Ca next opportunity, much more economical.

http://home.comcast.net/~jdieck1/chem_calc3.html

I would suggest adding 10 ml before going to work and another 10 ml when you get home. You should have it corrected in about 5-7 days. Just be sure to check the levels every morning to guage your success and be sure it's not going up too far (which I doubt). Also keep an eye on the alk, heavy Ca additions might push it down some depending on the Mg level.

Cheers
Steve

 

[Dr.Nate]

I forgot about Mg....how does it affect Ca again? And my dkh could stand to be lowered to 10 or 11...it's been high for awhile.

 

[Phyl]

Mg should be 3x your Ca so if it isn't up around 1300 you're going to have trouble getting your Ca up to 400+, in my understanding.

 

[Dr.Nate]

ugh...so does that mean I need to get a Mg test kit too? Along with a Mg supplement?

 

[malkore]

a Mg test kit...probably a good idea...but you may not need a supplement.

I would try dosing the calcium supp a few days and see if it helps first. You're doing exactly what I was doing: following their label and being a little cautious...when in fact you were underdosing and barely able to maintain your low level, let alone bring them up. My Mg level when I last tested was 1400ppm, which I attribute to occasional top-offs with my moderately hard tap-water (something I was experimenting with)

Steve-s gave me the same chemistry calculator link, and I realized that my 1/4tsp doses weren't enough since I needed over 8 full teaspoons to reach my target. daily doses of 1 tsp for a week got me on track, and now maintenance is much easier.

 

[steve-s]

I forgot about Mg....how does it affect Ca again?

Not much in regards to Ca at all, it helps alkalinity stay in solution against the Ca. If Mg is low, Ca will commonly be high or climb uncontrolabley. Low Mg will also inhibit alkalinity from gaining ground against the rising Ca. If you have a steady alkalinity, low Mg would not commonly be the issue. The only reason I mentioned it is when heavier than normal Ca additions are made with a less than desirable Mg level, alk will typically fall off as well. If your Mg is above 1200 ppm, I wouldn't worry about it much.

And my dkh could stand to be lowered to 10 or 11...it's been high for awhile.

It's a tad high but nowhere near dangerous, typical results for IO. Ideally you want it somewhere around 7.5-8.5 with a balanced Ca reading. Not much reason to go beyond that unless you have cronic pH problems. Once the Ca level is corrected, it will hopefully fall into balance. You'll just need to make sure you tweek the newly mixed saltwater before performing water changes to maintain that balance.

Cheers
Steve