ALK Issues-But Not The Expected

[JSM]

I have had my reef system up and running for almost 13 years, it's been very stable with the occassional issues but lately I have been totally stumped. Back in February my alk spiked to 14 dkh so I quit dosing (I use Randys 2 part) but it has only dropped to 10.2...I have used several different Salifert kits from different batches and they read the same thing. I have not added anything for alk since sometime in Feb. and it is not dropping. I use IO salt that is around the 4 yr mark, but I called IO and they said it is good for 5 yrs. I bought a large quanity from someone who used to work for the zoo when he got out of the hobby. I tried raising my cal to see if I could get the alk to drop and it does not. I tested the alk in my new saltwater for changes and it is around 9 dkh...did a fairly large water change last week and it is still at 10.2. What is causing my alk to remain so high when I have not added anything in months. SG is 1.026, Mag is a little high at 1500, cal is 480, temp runs from 78-80. I just loast an LTA that has been in that tank for 11 yrs, it had NEVER wandered and a few days ago it did and was a mushy mess the next day. I have 2 tube anemones that have been with me for around 13 yrs that are starting to shrink even though they are fed several times a week. And my blue carpet that is around 11 yrs is starting to do weird things also. Anyone have any idea why my alk is doing this? I also dose my own phytoplankton but have been doing that for 12 yrs, thought I'd throw that in there in case it might have any significance. Thanks so much!

Janna

[Randy Holmes-Farley]

What do you have in the tank that uses alkalinity?

Do you have a picture so we can see?

Do you use tap water?

No buffers of any kind?

FWIW, old salt won't add any more alk, and maybe less, than new salt. :)

[JSM]

I use RO/DI water, and have added no buffers since Feb. I have a mix of hard and soft corals, I have some monti's, favia's, acans, frogspawn, hammer, symphyllia, sarcophytons, xenia, clavularia, sinularia etc. Is it possible that something has settled in my sump or on the substrate that is precipitating out and causing it to stay so high? I have used your 2 part for years. I have dosed vodka for 4 yrs if that might mean anything.

Janna

[bertoni]

I'd run an ammonia test at this point, just to be safe. Some carbon might help, too. I'm not sure what's happening. Alkalinity at 10.2 dKH should be safe. Lots of people run at that level or higher.

[Randy Holmes-Farley]

The only thing I can think of that might slowly release alkalinity would be magnesium hydroxide. If you added a huge amount of the magnesium part to a low flow area and got a cloudy glob on the bottom that might happen, at least for a little while.

Otherwise, nothing should be dissolving (or precipitating) and adding alkalinity.

You sure the DI of the RI/DI is not depleted?

Maybe the hard corals are just not growing for some reason.

[shiladitya1991]

Subscribed.!!

[cham]

Do you have a deep sandbed by chance?

[JSM]

I have an inline TDS meter and I change everything as it needs to be changed. I'm not worried about the level that the alk is at, I'm just concerned about why it is not dropping. My sandbed is 3-4". I did change my lights to LED's back in February, started them out low and worked my way up to full intensity. Is it possible that the hard corals aren't growing because the change in light has put them into some sort of shocked state?
However, they all look as good as ever so I don't know if that has anything to do with it.

Janna

[Randy Holmes-Farley]

They might not be growing for that reason, or others, such as possibly elevated phosphate, organics, etc.