Alkalinity testing issues. Need help.

Danroo · Jan 29, 2022

I’vent been serious with testing my alkalinity lost first 3 hard corals cause of that maybe. Cause I’m still not sure if it’s alkalinity or my lights. So I’ve been using salifert test kit to test my waters. Because I’m not sure if I’m testing accurately I haven’t tested calc, magnesium, alkalinity, religiously like with other test kits. That changed last two week after I moved.

So I decided to buy the Hanna checker to get accurate results and easier testing. Before getting the Hanna checker I already bought cheap sps frags and lps frags. I’ve been keeping them in 8.6 dkh according to my salifert.

now the problem started when I got the Hanna checker and tested my waters and got 7.3 dkh. even though I did a water change yesterday. That just seems surprising low while having only soft corals and an anemone in the tank, while my salifert is telling me I have 12 dkh.

did my salifert gone bad or I got a faulty Hanna checker? Corals have been in my tank for a week now. They’re doing great.

T-J · Jan 29, 2022

Take a water sample to a LFS and see what they get. You could also send out for an ICP test and get a good reading on everything in your tank if you’re going to be getting into SPS.

Danroo · Jan 29, 2022

T-J said:
Take a water sample to a LFS and see what they get. You could also send out for an ICP test and get a good reading on everything in your tank if you’re going to be getting into SPS.

Thanks for the response I tested again. I was making a mistake of testing my salifert. Both are at 7.3ppm. I just can’t wrap my head around on how it could drop 1dkh in a day after doing a water change yesterday.
Also tested ph that came 8.0, I’m not sure what’s dropping my dkh so much.

Suohhen · Jan 29, 2022

That big of a drop isn't crazy but I would suspect that you are also experiencing a little variance with your Salifert test. It is hard to be consistent with that test but it is certainly way more consistent than their other tests. One recommendation I could make is to look up a YouTube video about how to use the kit. There are a few things you can do to make the process way more consistent.
Accurately tracking how much your alk is dropping per day is very important.

Suohhen · Jan 29, 2022

And yeah +1 on the ICP, just beware that the only one that tests alk is ATI. Er at least afaik, things change but alk it not something that can be measured with an ICP test. They run the water through a separate alk test.

Danroo · Jan 29, 2022

I looked up a brs salifert testing guide on alkalinity. That’s how I made both have similar numbers. I might have to switch to a different salt or the higher dkh fritz salt. Their site mentions that 1.026 will provide 8-9 dkh. I’ll do one more water change and see if it goes back to 8.3 or something.

Suohhen · Jan 29, 2022

Water changes are not an adequate way to keep stable alk. They make high alk salt for that purpose. One of the brands, i forget which, is the red bag. But you are basically just paying a premium for an extra little bit of sodium bicarb. If you are attempting to keep hard coral it is a must that you measure and dose accurately. Even if you aren't most tanks eventually develop a high enough demand regardless of whether you keep hard coral.

tanked4u · Jan 29, 2022

You may want to also double check your magnesium level. I had a problem maintaining Alk/Calc and eventually determined it was caused by low Mag.

Also, if you are using the Hanna Alk checker, make sure you keep the glass cuvettes clean by thoroughly flushing them after each test. The reagent can stain the cuvettes over time, and your readings will start going nutty. I learned this the hard way.

Danroo · Jan 30, 2022

Suohhen said:
Water changes are not an adequate way to keep stable alk. They make high alk salt for that purpose. One of the brands, i forget which, is the red bag. But you are basically just paying a premium for an extra little bit of sodium bicarb. If you are attempting to keep hard coral it is a must that you measure and dose accurately. Even if you aren't most tanks eventually develop a high enough demand regardless of whether you keep hard coral.

Funny thing is their high alkalinity which is 10-15 dkh is cheaper than the 8-9 dkh earlier I didn’t know the difference and bought the expensive one.

my tank is a 20 gallon so I think I can get away with water changes if alkalinity isn’t dropping 1dkh every day. I’m still not sure if my dkh was very low last week due to inaccurate testing. Now I know how to properly test and see if I should start dosing from now on.

Danroo · Jan 30, 2022

tanked4u said:
You may want to also double check your magnesium level. I had a problem maintaining Alk/Calc and eventually determined it was caused by low Mag.

Also, if you are using the Hanna Alk checker, make sure you keep the glass cuvettes clean by thoroughly flushing them after each test. The reagent can stain the cuvettes over time, and your readings will start going nutty. I learned this the hard way.

I checked my calcium and magnesium at the same time. Magnesium was shooting 1500. And calcium 480. Other elements are fine besides low dkh.

Aqua Man · Jan 30, 2022

Danroo said:
my tank is a 20 gallon so I think I can get away with water changes if alkalinity isn’t dropping 1dkh every day. I’m still not sure if my dkh was very low last week due to inaccurate testing. Now I know how to properly test and see if I should start dosing from now on.

Coralline algae is a big consumer of Alk.