Help - STN?

markalot · Feb 13, 2018

Question,

why did your Alk drop that much over just a week? Base recession is usually caused by fluctuating Alk, which it seems like you have. Are you using a doser?

Nitrates and PO4 are not ideal but fine IMO, unless they are rapidly fluctuating as well. Instability usually leads to STN from the base in my experience, fix the instability issues and it should slowly recover.

tenurepro · Feb 13, 2018

markalot said:
Question,

why did your Alk drop that much over just a week? Base recession is usually caused by fluctuating Alk, which it seems like you have. Are you using a doser?

Nitrates and PO4 are not ideal but fine IMO, unless they are rapidly fluctuating as well. Instability usually leads to STN from the base in my experience, fix the instability issues and it should slowly recover.

I usually use kalkwaser in my ATO, and that takes care of most of my Alkalinity demands. I supplement with Red Sea foundation Alk buffet via auto doser. The ato does fluctuate a bit depending on house temp and relative humidity, hence the drop I think... I’ve had more substantial changes without much of an affect in the past

markalot · Feb 14, 2018

tenurepro said:
I usually use kalkwaser in my ATO, and that takes care of most of my Alkalinity demands. I supplement with Red Sea foundation Alk buffet via auto doser. The ato does fluctuate a bit depending on house temp and relative humidity, hence the drop I think... I’ve had more substantial changes without much of an affect in the past

It will depend on the overall health of the acro. If it's otherwise in great health then damage may be slight or no damage done. If health has declined due to other issues, be it poor lighting or starvation, or those previous substantial issues, then damage is usually worse. There are a few long time SPS keepers who keep near perfect systems. Acro health is outstanding, growth is outstanding. They can accidentally fluctuate Alk, and end up with no to just minor damage. Do this in a new tank or one that has had past stability issues and you end up with a bunch of white skeletons. IMO understanding the health of the acro and warning signs when not in good health is one of the biggest steps to keeping these things long term.

I used a timed topoff with Kalk so the dose is always the same. Evaporation does vary but generally I can control by having a fan on more often or manually adding topoff once a week. Most folks that use Kalk just drip it on a regular basis at a rate below that of topoff requirements and put only water in the topoff.

One other warning sign here is you mention using Red Sea Alk on a doser. What about calcium? If you only dose Alk eventually you will reach an imbalance. All dosing, if you choose to dose, should be two part and equal amounts both parts, based on your Alk reading. Both are used equally, even if your testing doesn't show it. The scales are different so a drop of 1 KH is still in the error range of the calcium kit.

The above applies mostly to acros in my experience. I hand dose my smaller tank, a 40 gallon. Any acro in here browns out and dies after a couple of months because I don't keep it that stable. None of the other SPS have any issues at all, other than slowing growth if I let Alk fall below 6.

It's the annoying and beautiful Acropora that cause all of our headaches.