High Alk Problem
 

So, yesterday on my lunch break I went home and noticed a bunch of air in my Alk. dosing line. So I manually overrode the controller and ran the dosing pump to take all the air out. Phone rang, then other things happened and I ended up leaving the pump on for 5 hours. Tested alk when I got home (6 PM) and it was almost 11 (I normally run the tank around 8.0).

This has happened to me once before, and a bunch of SPS receded from the bottom up. I feel like an idiot who doesn't learn, ever!....

What can I do? I tried changing some water, but I didn't have a lot made up and it didn't even put a dent in the alk. I would hate to see my SPS recede again...

Some stats: Mixed SPS and LPS tank. 150 gal cube, 40 Gal sump, and 55 gallon refugium all plumbed in. Typical params: Ca 410-420, Alk 7.8-8.4, Temp 78, Phosphates 0.02-0.06, nitrates undetectable. I run GFO and biopellets. Photon 32 Reefbreeder/Evergrow lights. Reefkeeper Elite controller.

In desperation I prepared a small batch of saltwater and did a 15 gallon change. To my shock, the KH went up slightly. I had just opened a new bucket of IO salt. So, I tested the new water (after the fact) and found the Alk to be 12.8 dKH. What the heck?....

Everytime I mix IO I always get 10.5 - 11.5. Thought this was common knowledge (?).

Totally sucks if you're trying to run Zeo. Sorry to hear.

Fwiw, muriatic acid will lower alkalinity and not affect other parameters. I have no idea how much you would need to add. It would be a very small amount. I've not actually heard of anyone using it in-tank though. I'm certainly not recommending it - just putting it out there for you to consider looking into.

What's your calcium at?

Thanks Mindy. I had no idea. I do have Muriatic acid, ; I may add it to the new water if the Alk doesn't go down soon.

Yesterday it was at 430. Normally I keep it between 410 and 430.

Thanks for the info. 12.8 was a bit of a shock to me. Not trying to run Zeo. I do run biopellets though. I prefer my alk around 8-8.5 dKH.

That's odd that your calcium didn't dip down. Usually it does, and then if you raise it up you can get the alkalinity to go down a bit. If your magnesium is around 1400 ppm you could increase calcium to about 465 ppm (Mg 3x the value of Ca). If it was me, I'd try to get all of the "big three" raised up so that they are closer to balanced, and then stop dosing and let them fall on their own.

+1. Thats what i would do as well. 11dkh is a bit high but not dangerously high. I usually keep my alk around 10-10.5. Hope you get it figured out.

If you add a lot of calcium with your alk that high and your mg isn't high too, its going to calcify all over the place including your pumps! Be really careful if that's the plan.

Ha; the alk is now sitting at 7.9. Ca at 425. Mg at 1410. I stopped dosing Alk for less than 48 hours, but left the Ca doser on its normal schedule (dosing for 9.5 min every hour, 20 times a day). So, in less than 48 hours, my corals burned through nearly 3 dKH units of Alk.

Do plants have anything to do with Alk consumption? I have a 55 gallon refugium that growns cheato and caulerpa like a champ! Because I like my fish fat and happy!

Let's hope the SPS don't suffer from the spike...