Adding Calcium

[Havok1071]

So I have a mixed reef 40 gallon tank. I just bought a Red Sea foundation pro kit and have tested the calcium. It’s reading at 290. Everything I’m reading says it should be much higher than that. My question is, is it on to add 20ppm per day to increase it to 400-450ppm or do I add it weekly?

 

[Riphter]

Slow and steady. I had a drop after some stony additions. Down to 360. I bumped it up over the course of a few days. Also check your water after you mix your salt. Regular water changes shouldn’t let it get this low. Might have to adjust the calcium level in your water after mixing. Check your mag as well. They kinda go hand in hand. Have a lfs or fellow reefer double check your calcium as well. I had a test start failing on me. For nitrates, but it can happen.

 

[Uncle99]

I think that’s reasonable.
Make sure MG is in the 1260-1360 range, before adding CA, or you might find it hard to hit the target.

 

[Riphter]

+1 for checking mag too. They go hand in hand.

 

[Havok1071]

I added 40 ml of calcium, the corals have shrunk a bit. Is this normal? It’s my first time adding calcium so I don’t know what to expect

 

[Uncle99]

I don’t know what the concentration of your supplement is in dosing volume, but increase of 20ppm in CA is fine. Once you hit your target, then you need to calculate your daily consumption so you know much to dose daily. The smaller and more frequent the dose, ( for anything) the more stable your tank is.
You should pay great attention to ALK, this one can change fast as there’s not so much in the water.
Salinity and Alk are cornerstones.
Stability is everything.

 

[ShannonC]

I think that’s reasonable.
Make sure MG is in the 1260-1360 range, before adding CA, or you might find it hard to hit the target.

Apologies for jumping in on this thread, I have my own query on low calcium levels. We have very low calcium (around 300ppm) at the moment and have been really struggling to get it to increase. We have calcium flake and FluvalSea liquid calcium; added about 180g of calcium flake over 2 days and no change and then added in about 150ml of FluvalSea calcium and there is no change. We haven't got a mag testing kit so can't do that but if we have low mag can this stop the levels of calc increasing at all? Our alk & pH seem fine although pH maybe a touch high (9/10dKh & 8.2/8.4). Our corals are starting to look seriously sad now so any advice would be appreciated. Thanks!