Alk very low..

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Thanks for the replies.

I use h2O salt. All of the properties while testing seem perfect, even somewhat higher than the norm.

My tank is a 72g, 20g sump, skimmer, np reactor and I do 20% bi-weekly water changes. No dosing at the moment, except for the odd capful of purple-up when my calc is getting lower.

My salt is at 1.023...I'm starting to question the accuracy of my refract meter though, it's one of those cheapo see-through ones with the blue gauge. I've had it for a couple of years.

I switched test kits and have the same result.

So let me get this straight... BAKED baking soda raises PH, not Alk. NON BAKED baking soda only raises ALK?

I'm going to take a sample to my LFS just to confirm everything this weekend. It just doesn't make much sense to have good readings except with alk. Then again, I've been in this hobby for almost 2 years and nothing makes sense at first.

Thanks again for the replies and links.