Crazy amount of Alk & Calc consumption ... what could be wrong?

Brian Lenny · Sep 29, 2019

Hi everyone,

I have a 280G display + 40G sump. Established for 7 months, about 20 LPS and soft corals (medium to large size). I'm dosing 600ml of Alk and Calc daily and 500ml of Mag (every 4 days). I'm still dropping Alk levels by 0.2 dKh per day (measured by Hanna checker). I'm using BRS brand Alk, Calc and Mag.

According to the calc on the BRS website, if I'm still dropping that means I'm consuming greater than 3dKh per day. I know that coraline can consume a lot - but, this seems a bit crazy

My levels are: 420 Calc; 8.0 dkh; 1400+ Mag.

I don't see precipitation on the rocks, heaters, pump etc. Should I up the dose even more? Any thoughts appreciated!

Flyingbulldog · Sep 29, 2019

Wow thats a crazy amount! Hopefully someone can chime in and suggest something.

JBKReef · Sep 29, 2019

Any chance you have a clam?

Brian Lenny · Sep 30, 2019

Nope, no clams. I have a few Euphylias, a few Leathers and 3 Anemones.

reefproaquatics · Sep 30, 2019

Are you using sodium carbonate or sodium bicarbonate? I feel that the latter is more stable over time. In any case you may find that cutting back on the amount of calcium you are adding allows your alk to increase without having a terribly negative effect on the calcium level itself.

Brian Lenny · Sep 30, 2019

Hi,

Thanks for your reply. I'm using Soda Ash or sodium bicarbonate (from Bulk Reef Supply). I have tried lower Calc dosing, but don't see a difference in Alk.

Plus, much of what I've read (from Randy and others) warns about keeping ionic balance across Alk and Calc.

Dkeller_nc · Sep 30, 2019

Note that "soda ash" is not the same as sodium bicarbonate. Soda ash is a common name for sodium carbonate, and the 2-part solution recipe on BRS's site for sodium carbonate is roughly twice as concentrated as sodium bicarbonate as far as alkalinity is concerned. So if you're dosing a sodium bicarbonate solution, but estimating alkalinity consumption as sodium carbonate, you'd be off by 1/2.

JBKReef · Sep 30, 2019

Are you measuring the actual output of the dosers? is it possible the calibration is offf and you're not dosing as much as you think you are?

BeejReef · Sep 30, 2019

What alkalinity level are you attempting to maintain?

Silent · Sep 30, 2019

Is you substrate turning into concrete yet? I bet your water is super saturated. That seems to be too much dosing especially the mag.
Might be worth checking this out.

Brian Lenny · Sep 30, 2019

Thanks for all the replies.

(1) I'm using Sodium Carbonate - I made an error in a previous response. The Soda Ash from Bulk Reef Supply is listed as Sodium Carbonate. According to BRS Calc, 200ml should move a 280G tank by 1.9 dKh

(2) I've checked the level in my dosing container, and it's moving down by ~600ml per day, so the doser is calibrated

(3) I'm trying to maintain 9 dKh. As it is, the only way I can increase is by doing a bulk addition (eg., 1.5 tablespoons = roughly 1dkh in the tank) but by the next day, it's back down

(4) My substrate is fine -- still nice and sandy

I'm really at my wits end here. I've watched the video and I don't see precip when the doser adds. And after a few hours of addition, the Alk definitely goes up. But the next day, it's down again

I'm using Kent Reef Crystals, which mixes around 8dKh. My next thought is to use Red Sea Coral Pro, which mixes around 10dKh and maybe with that I'll have better luck keeping the dKh level higher?

Any other ideas folks?

Brian Lenny · Oct 2, 2019

I tested today, and the Alk was 7.2 (down from 7.9 48hrs ago) and Calc is at 480, Mag at 1470. What is can't figure out is why Alk is dropping while Calc and Mag is so high. Any thoughts?

BayouReefer · Oct 2, 2019

I’m not sure but could your salt mix have chelated calcium? If so chelated calcium still will test but that ion is not available for the coral or coralline to uptake.

BayouReefer · Oct 2, 2019

Maybe this will help

Michael Gray · Oct 2, 2019

This is interesting video. So is he saying. Alk will not be stable with a ph under 8.2? Is it not possible to have alk 9dkh with a 8.0 ph?

Mortie31 · Oct 2, 2019

You have got to have precipitation somewhere, as from what you have described the corals aren’t big enough to be consuming those amounts, have you checked your sump for white deposits? Check the area around where you dose... make sure you are dosing into a high flow area and allow at least 15mins between dosing ALK and Ca.

Silent · Oct 2, 2019

So what is your ph? I am curious if it is dropping with your alk.
I think you need to do a water change but first test the new saltwater and see what the parameters are before adding it to the tank. Your cal is high and if you understand cal and alk are on a teeter tooter. If one goes up the other goes down. The water only holds so much total. Higher mag in your case will let both those numbers go up but it is still like a teeter tooter. The lower your cal the higher you can get your alk to that 9dkh you want.

Jeff Jarry reef · Oct 2, 2019

The first place precipitation takes place is on heaters in my experience with that. IMO you might want to check them as well. Good luck that is crazy high

Mrx7899 · Oct 2, 2019

I agree with mortie31 your probably adding to much and its precipitating out or your magnesium is really low and its making it hard to keep alk and calcium stable.

IKD · Oct 2, 2019

Have you checked any of your plumbing? I had a similar situation a couple years back and the precipitation was happening in my return plumbing. It looked like the arteries of a 500lb man working at Burger King...