Removing calcium from sand bed/tank?

[Chronicj7]

I used a bit of DIY live rock and it boosted my calcium levels to nearly 800 ppm. I have since then removed all the DIY rock and replaced it with cured fiji and have been doing water changes to bring the calcium back to normal. The problem is, I can't seem to get it below 500 ppm. I'm not sure if its soaked into the sand and thats releasing it now or if the rock may have released something else into my tank but my SPS aren't opening polyps.

I need some advice as I have about $400 worth of coral on its way.

 

[MHG]

$400 worth of coral will drop it... My tank was at 500 for the longest time. High but not deadly (at least what I have seen here on RC)

 

[Chronicj7]

My fear is that I will lose a lot of them =(

 

[nanojg]

I dont understand how the rock or sand would release calcium at the ph levels of a reef tank???

 

[Sk8r]

Your calcium and alk are 'locked' with your mg reading. If the mg is up, neither alk nor cal will fall. Your water changes are about the best method to get it down, but watch the mg reading and be careful that once mg drops, everything should be in the ratio you want before you bring it up again.

 

[Chronicj7]

DIY rock that isn't cured in saltwater for a bit can leach calcium...I had an 800 reading before so my only guess is that the sand absorbed enough to keep its above 500. I am dosing alk almost every day to keep it between 8-9. Water changes are my only way of lowering the mg?

 

[Sk8r]

As far as I know, but beware of buffering too much---first off, be aware I'm no chemist, and disk one could better help you---but I do know if you have a high buffer load in your system it can end up with deposits in your pipes. I had calcium carbonate in my hoses, had to replace some (Basement sump) and then ended up having to replace the bottom bulkhead in a corner tank (that was a job) because I had an expired alk test---and I would advise cross-checking your calcium test to be sure you've got a good reading. I think just continuing the water changes---it's the only thing I can think of that would remove the magnesium. Once mg drops below 1200, I would expect a slow fall in calcium and alk.

 

[bertoni]

500 ppm of calcium should be safe. People run higher with no problems. What is the calcium level of some freshly-mixed saltwater? Some salt mixes read that high out of the container.

Water changes are the only way to lower calcium and alkalinity levels in a tank, other than waiting. Changing the magnesium level won't help with this problem, in any case. The rate of abiotic precipitation is too small to have a measurable effect unless magnesium gets far too low.

 

[Sk8r]

Ah, now we have someone who knows. Thanks, Bertoni!

 

[Chronicj7]

I've cross checked it with a friends test kit as well as my LFS. It's spot on. My pre mixed water is about 7 dkH and 380 calcium at 1.025 sg. I just checked it agains as I did a 10g water change late last night. It's finally at 480 ppm. HEW:

The only other thing I'm somewhat worried about is if those DIY rocks leached something else into the tank which is why some SPS aren't very happy.

 

[Sk8r]

I would surmise that the sps are upset at the sudden changes in water: they're not inclined to like change very much, and every time you add 'different' water they're going to have to adjust their own tissues to the change. Let them settle a bit and let things normalize and they may respond.

 

[Chronicj7]

Alrighty. Thanks for all the insight!

 

[SputnikNYC]

I've cross checked it with a friends test kit as well as my LFS. It's spot on. My pre mixed water is about 7 dkH and 380 calcium at 1.025 sg. I just checked it agains as I did a 10g water change late last night. It's finally at 480 ppm. HEW:

The only other thing I'm somewhat worried about is if those DIY rocks leached something else into the tank which is why some SPS aren't very happy.

500 is safe, ones you put the corals in, you'll have another problem, keeping it up :spin2: