Need help urgently: Calcium and Alk levels dropping in SPS tank!

[ml708]

Great forum!

First thing I saw was the sticky on calcium and alkalinity levels, and I add calcium and carbonate in equal proportions each time so I'm not sure what is going on.

There is a problem with my 100g SPS tank. Calcium levels can drop from 420-350mg/ml, and alkalinity level drops from 4.5-3.5meq/l in one day. This is worrying as I do not know the root cause and if I keep topping up the calcium and alkalinity levels so rapidly, it will kill my corals and my wallet.

Some background info on the tank

3 acros around 4 inches high and 1 LPS duncan coral (quite big around 30 heads)
Some hermit crabs, sea squirts and feather duster worms
pH 8.3-8.4
Salinity 1.0265
temp 26.2-26.7
Nitrates 0
Phosphates <0.08 (my test kit shows very little deviation below this level)
magnesium 1440 (alittle high I know)
additives (ultra min fine food for sponges, phytogreen 10-15micrometer phytoplankton 1ml/day, polyplab polyp booster 1ml/day, ultra minS nutrition concentrate 1ml/day)
Have a skimmer and phosphate reactor running

I usually add the calcium and carbonate powder to the sump. Measurements in the main tank and sump have no deviation.


Could anyone please advise?

 

[bigworm175]

How are you adding the calcium and carbonate? I mean what exactly are you dosing? Is it a brand of additive or a DIY? Most powdered additives need to be dissolved in water before adding. It is also advisable not to add them at the same time if adding to the same area of tank. You don't want it to precipitate.

Also, what is your method of testing? Are you testing immediately after dosing?

 

[ml708]

I add seachem reef builder and grotech calcium pro instant. I normally swirl them around in a small amount of DI water and then add that to the overflow compartment that drains to the sump. I did notice that a small amount did precipitate though.

I test about an hour after dosing, when the water has become less cloudy.

 

[cugly]

I suggest get a calcium reactor or a dosing pump so you will have a more stable parameters. .

 

[tektite]

Do you dose them at the same time?

Are you saying the tank remains cloudy for over an hour after dosing? If so, that's where your 2 part's going.

How much coralline algae do you have?

If you're going to do 2 part and you use that much, you should look into cheaper alternatives like BRS. You'll save a TON of money that way.

 

[bigworm175]

Are you swirling them together before you dose? If so, don't. Either dose them at different times (probably best) or for small doses, dose one in sump (alk.) and the other into the display (ca.) It sounds to me like you may be wasting much of your additives by precipitation before it gets into your water.

Like Tektite said, I would find a more affordable solution like the DIY. For your demands I would think manual dosing can work but if your demands go up (growth/additions) or your patience wains then you may want to look into dosing pumps, kalk or even a calcium reactor. Stability, stability, stability.

BRS 1.1 ml. dosing pumps are on a big sale right now if you are considering that route. A controller can run them but so can a fairly cheap timer from your local drug store.

 

[ml708]

I have a few scattered small colonies of red coraline algae on my live rock.

Do you guys have an estimate of the amount I should rationally expect the ca and alk to decrease in a daily basis in my setup?

As for dosing pumps, are they able to electronically read the amount of ca/alk in the water and automatically dose the required amounts?

 

[tektite]

Are you dosing them together or at different times, and if so how much time do you allow between each one?

 

[ml708]

I dose at different times (depending on which is high or low). When both are low, I made the mistake of dosing both at the same time, which I know now not to do. I just measured my alk, its 4.5meq/l which is good. Ca is low though so I will be dissolving in small batches in DI water and report back on the levels.

 

[ml708]

I just dissolved a small amount in a bucket. Seems that no solids are left but the calcium solution is forming a denser layer under the DI water. Wondering if this is to be expected or how to rectify it