low Alk high calcium

[Accidentalreefers]

Hey everyone so I'm new to the whole dosing thing, I've noticed my alk has been on a constant decline, it went from 8.2-7.5 this happened over the span of about 8 months, after I did a 40% water change my alk still sat at 7.5 so i decided to hand dose Red sea foundation B liquid I run a 75G tank I deducted my displacement and on the calculator it told me to dose 25ML to get back to 8.5dkh i dosed that amount right off the hop I checked my alk a day later and it's at 6.4????? What would be the best thing I do in this case none of my corals are showing signs of stress I'm using Salifert test kit.
Tank isnt to stocked have a mix of sps and lps, that are on the smaller side i do have a large birds nest colony about 7"x 5"

Alkalinity 6.4
calcium 430
magnesium 1250

 

[Reefer5640]

I would test a couple hours (depending on tank turn over) after dosing to see the true effects of the amount you dosed. Waiting a day leaves a big margin of error due to consumption. Test daily for the next 2-3 days to get an idea of consumption. Once you get that figured out you’ll have a better idea of usage. I know you said you’ve been watching for 8 months but as things mature they consume more. Is it possible the test kit or method used could be producing inconsistent results?

 

[Accidentalreefers]

I would test a couple hours (depending on tank turn over) after dosing to see the true effects of the amount you dosed. Waiting a day leaves a big margin of error due to consumption. Test daily for the next 2-3 days to get an idea of consumption. Once you get that figured out you’ll have a better idea of usage. I know you said you’ve been watching for 8 months but as things mature they consume more. Is it possible the test kit or method used could be producing inconsistent results?

Thanks for the Intel, I'm going to get a hanna tester it feels crazy to me that im having such a big negative alk swing like this...