Strange Calcium results, seem to be dropping

[raynist]

I have been adding the 2 part alk/calc recipe for the last 5 weeks to my 75g sps/clam tank with 20g sump.

Here are my testing results starting on day one:

1/2/06 Alk 8* Ca 375
1/20/06 Alk 8* Ca 400
2/15/06 Alk 9.3 Ca 350

I have been adding 80ml a day of both solutions (recipe #1).

Would there be any reason my alk is increasing but my Ca is decreasing?

This tank has 2 clams (3 inch) and about 10 small acro frags (1-2 inches).

I tested Mg today for the first time and it was 1290 (salifert). PH is usually 8.0 - 8.2.

Thanks
Ray Nist

 

[steve the plumb]

your mg is fine but I would raise it to 1350.Your corals are absorbing it faster than the calcium that is normal.Do you have alot of coraline algea and do you have calerpa in your sump.Both use up alot of calcium.How long have you had all the acros.If you started to dose regular and feed the acros at least 3 times a week you will notice how fast they will start to grow.I find it takes a couple of months for the acros to get used to the tank enviornment and then they start to take off with regular dosing and feeding.

 

[raynist]

The tank has only been setup since Xmas. There is a good amount of coraline on the rocks (from an existing tank), but really no where else. I have had the acros about 5 weeks or so.

I haven't fed them much at all. I have a hawkfish in the tank and nothing else (other than snails). I feed him 2 flakes of food a day. He eats shimp and othet things that grow in the sump. I use chaeto in the sump. I have only fed the corals 2x's using DT's oyster eggs.

Should I dose more Ca than Alk, or raise them both to 120ml a day?

BTW, I had a SSB and removed it this past weekend as the sandstorms were bothering me.

Thanks
Ray

 

[steve the plumb]

I would feed the acros at night at least 3 times per week.I found that my tank at one point consumed so much calcium then it leveled off.This was at the stage where coraline was starting to take off.You can dose more to get desired levels.You can use Randy Reef Calculatoer to see how much to dose if you are worried about dosing to much.I would also test after dosing.I wait about half an hour then I test.Then dose the next day again test again.You can icrease the dose daily if you want then tset every day when levels become more stable you will see how much dosing your tank requires.Don't forget your tank is new so when you add more acros wich you will you may find you have to dose more.This will becoma a habit once you find the right dose its not that hard just don't become lazy test at least once a week no matter what it doesn't take that much time plus you don't want something to go wrong only to find out that you could have prevented it but you were just lazy got into the grove and stop testing.I test twicw a week weather I have to or not.Like I said I try to make it a habit just like a water change.My other friend tests twice a day.Thats a little to much but he wants to know the paramaters.

 

[raynist]

Thanks Steve!

 

[steve the plumb]

Your welcome.Clams need to eat aswell.

 

[Randy Holmes-Farley]

I wouldn't look at those numbers and necessarily conclude that calcium is dropping (as opposed to noisy testing), but it may be, and there is nothing wrong with boosting it. Just add enough of the calcium part all at once to push it to 420 ppm. This calculator shows how much to add:

Reef chemicals calculator
http://home.comcast.net/~jdieck1/chem_calc3.html

The calcium can decline for a variety of reasons, including water changes with a low calcium mix (like IO), or imperfect formulation of the two part (for example, due to moisture in the calcium chloride). If it routinely drops some, you can either make the next batch of the calcium part a bit more concentrated, or just give an occasional extra dose of the calcium part.

FWIW, I recommend 1250-1350 ppm for magnesium.

As to the daily dose, gauge it based on alkalinity, and yours looks fine right now, so 80 ml per day is probably fine.

 

[raynist]

Thanks Randy. I recently did a 25 gallon water change (IO) and then tested last night. maybe that is why the Ca number was lower.

Thanks
Ray

 

[Randy Holmes-Farley]

IO often has calcium around 350 ppm or so, so that may be part of it.

You're welcome and Happy Reefing.

 

[steve the plumb]

Randy knows all!!I find he is the only one who answers all the questions in full and doesn't leave you on pause.